Ch.14 - Chemical EquilibriumSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Sections
Chemical Equilibrium
ICE Chart
Le Chatelier's Principle
The Reaction Quotient
Additional Practice
Equilibrium Expressions

In order to calculate the equilibrium concentrations of compounds we need to use an ICE Chart. 

Calculating Equilibrium Concentrations

Concept #1: Understanding an ICE Chart 

An ICE Chart should be used when we are missing more than one equilibrium amount for compounds in our balanced equation. 

Since our equilibrium constant K is involved in an ICE Chart then we must continue to ignore solids and liquids. 

Example #1: We have a solution where Ag(CN)2 (g), CN (g), and Ag+ (g) have an equilibrium constant, K, equal to 1.8 x 10-19. If the equilibrium concentrations of Ag(CN)2 and CN are 0.030 and 0.10 respectively, what is the equilibrium concentration of Ag+?

Example #2: We place 2.5 mol of CO and 2.5 mol of CO3 in a 10.0 L flask and let the system come to equilibrium. What will be the final concentration of CO2?  K = 0.47

Practice: For the reaction: N2 (g) + 2 O2 (g) ⇌ 2 NO2 (g), Kc = 8.3 x 10 -12 at 25°C. What is the concentration of N2 gas at equilibrium when the concentration of NO2 is twice the concentration of O2 gas?

Example #3: When 0.600 atm of NO­­2 was allowed to come to equilibrium the total pressure was 0.875 atm. Calculate the Kof the reaction. 

Example #4: An important reaction in the formation of acid rain listed below.

2 SO2 (g)   +  O2 (g)  ⇌  2 SO3 (g)

Initially, 0.023 M SO2 and 0.015 M O2 are mixed and allowed to react in an evacuated flask at 340 oC. When an equilibrium is established the equilibrium amount of SO3 was found to be 0.00199 M. Calculate the equilibrium constant, Kc, for the reaction at 340 oC. 

Example #5: If Kc is 32.7 at 300oC for the reaction below:

H2 (g) +  Br2 (g) ⇌  2 HBr (g) 

What is the concentration of H2 at equilibrium if a 20.0 L flask contains 5.0 mol HBr initially?

Practice: At a given temperature the gas phase reaction: N2 (g) + O2 (g) ⇌ 2 NO (g) has an equilibrium constant of 4.00 x 10 -15. What will be the concentration of NO at equilibrium if 2.00 moles of nitrogen and 6.00 moles oxygen are allowed to come to equilibrium in a 2.0 L flask.

Example #6: Consider the following reaction:

COBr(g)  ⇌  CO (g) + Br(g)

A reaction mixture initially contains 0.15 M COBr2. Determine the equilibrium concentration of CO if Kc for the reaction at this temperature is 2.15 x 10-3.

Additional Problems
A hypothetical reaction is shown below. 2A(g) +B2(g) ↔ 2C(g). A flask of 1 L volume is charged with 0.382 mol A and 0.0952 mol of B2 and allowed to come to equilibrium. At equilibrium, the vessel is found to contain 0.0624 mol of C. What is the value of Kc for this reaction? A) 0.190 B. 1.79 C. 0.00193 D. 2.46 E. 0.596
At a certain temperature, 0.91 mol of NO is placed in a 1.0 L vessel. Once the equilibrium is established, 0.22 mol of each product is present. What is the Kc of the reaction? 2 NO (g) ⇌ N2 (g) + O2 (g) A. 0.22 B. 0.81 C. 1.2 D. 1.0
When excess PbCl2 is dissolved in 1.00 L of water, 0.032 mol of Cl − forms at equilibrium. What is the Kc of the reaction: PbCl2 (s) ⇌ Pb2+ (aq) + 2 Cl − (aq) Kc = ? A. 1.0x10−3 B. 1.3x10−4 C. 3.3x10−5 D. 1.6x10−5
Consider the reaction below: CaS (aq) + MgSO4 (aq) ↔ CaSO4 (s) + MgS (aq) If K is 20 and the initial concentrations of CaS, MgSO4 and MgS are 0.5 M, 0.6 M and 0 M respectively, what is the equilibrium concentration of MgSO4? 1. 0.1 M 2. 0.4 M 3. 0.2 M 4. 0 M
Carbon monoxide gas reacts with hydrogen gas at elevated temperatures to form methanol according to this equation: CO (g) + 2 H2 (g) ⇌ CH3OH (g). When 0.4 moles of CO and 0.30 moles of hydrogen gas are allowed to reach equilibrium in a 1.0 L container, 0.05 moles of methanol are formed. What is the value of Kc? 0.50 3.57 1.7 5.4
1.75 moles of H2O2 were placed in a 2.50 L reaction chamber at 307ºC.  After equilibrium was reached, 1.20 moles of H2O2 remained.  Calculate the equilibrium constant, Kc, for the reaction 2 H2O2(g) ⇋ 2 H2O(g) + O2(g). A)  2.0 x 10–4    B)  2.3 x 10–2    C)  2.4 x 10–3    D)  5.5 x 10–3    E)  3.9 x 10–4
When heated at high temperatures, a diatomic vapor dissociates as follows: A2 (g) ⟺ 2A (g) In one experiment, a chemist finds that when 0.0520 mole A 2 was placed in a flask of volume 0.527 L at 590 K, the fraction of A2, dissociated was 0.0238.   a) Calculate Kc for the reaction at this temperature                   b) Calculate Kp for the reaction at this temperature    
Consider the reaction shown below at 2200 °CN2 (g) + O2 (g) ↔ 2 NO (g)        K c = 0.0505A student adds 0.375 mol of N2 and 0.375 mol of O2 to a 2.50 L flask and then allows the reaction to come to equilibrium. What are the equilibrium concentrations of all reactants and products? 
The reaction NO2 (g)  +  NO (g)  ⇌   N2O (g)  +   O2 (g) reached equilibrium at a certain high temperature. Originally the reaction vessel contained the following initial concentrations: 0.184 M N2O, 0.377 M O2 , 0.0560 M NO2 and 0.294 M NO. The concentration of NO2 , the only colored gas in the mixture, was monitored by following the intensity of the color. At equilibrium, the NO2 concentration had become 0.118 M. What is the value of Kc for the reaction at this temperature? 
A flask is filled with sulfuryl chloride, SO2Cl2 and has an initial concentration of 0.168 M. If the flask is allowed to come to equilibrium according to the reaction shown below, what is the concentration of SO2 in the flask at equilibrium?SO2Cl2 (g) <==> SO2 (g) + Cl2 (g)   Kc = 2.32 x 10 -7A. 1.97 x 10-4 MB. 0.00851C. 3.90 x 10-8 MD. 4.39 x 10-4 ME. 1.62 x 10-4 M
Consider the following reaction:CH4 (g) + 2H2S (g) ↔ CS2 (g) + 4H2 (g)A reaction mixture initially contains 0.680 M CH 4 and 0.520 M H2S. When equilibrium is reached the concentration of H2 is determined to be 0.250 M. What equilibrium concentration of H 2S?a. 0.270 Mb. 0.583 Mc. 0.0200 Md. 0.395 Me. 0.458 M
For the reaction, CO(g) + Cl2(g) ⇌ COCl2(g)       Kc = 255 at 1000 K. If a reaction mixture initially contains a CO concentration of 0.1550 M and a Cl2 concentration of 0.171 M at 1000 K.What is the equilibrium concentration of CO at 1000 K?What is the equilibrium concentration of Cl 2 at 1000 K?What is the equilibrium concentration of COCl2 at 1000 K?
The equation for the formation of hydrogen iodide from H 2 and I2 is: H2(g) + I2(g) ⇌ 2HI(g) The value of Kp for the reaction is 71 at 710.0 °C. What is the equilibrium partial pressure of HI in a sealed reaction vessel at 710.0 °C if the initial partial pressures of H2 and I2 are both 0.100 atm and initially there is no HI present?
At a certain temperature, A2 and B2 react to give AB as follows:A2 (g) + B2 (g) ⇌ 2 AB (g)                            K   c = 0.354If an 8.00 L flask initially contains 4.16 moles of A 2 and 4.16 moles of B2, find the equilibrium concentration of AB in the mixture.A. 0.142 MB. 0.175 MC. 0.119 MD. 1.91 ME. 0.238 M
Ammonium Iodide dissociates reversibly to ammonia and hydrogen iodide:NH4I(s) ⇋ NH3(g) + HI(g)Kp = 0.215 at 400°CIf 150 g of ammonium iodide is placed into a 3.00 L vessel and heated to 400°C, calculate the partial pressure of ammonia when equilibrium is reached. Hint: Ammonium Iodide is a solid, is it used in the equilibrium calculation? 
A reaction mixture initially contains [N2O4] = 0.0250M. Find the equilibrium concentration of NO2.N2O4(g) ⇌ 2NO2(g)                                K   c = 0.36A) 0.054 MB) 0.140 MC) 0.005 MD) 0.041ME) 0.027 M
At a certain temperature, 0.0740 mol of PCl 5(g) were introduced into a one-liter container.PCl5(g) ⇋ PCl3(g) + Cl2(g)At equilibrium the concentration of PCl 3(g) was 0.0500 mol/L.a) What were the equilibrium concentrations of Cl 2(g) and PCl5(g)?   b) What is the value of Kc at the temperature of the experiment?
For the equilibrium, SO2(g) + NO2(g) ⇌ SO3(g) + NO(g) The four gases are mixed in a container in the following partial pressures (in atmospheres): SO 2 (2.3); NO2 (2.8); SO3 (1.4); and NO (3.4). At equilibrium it was found that the SO 2 partial pressure was 2.8 atmospheres, what is Kp? a) 0.28 b) 1.79 c) 2.87 d) 0.134 e) 3.54
At a certain temperature, the equilibrium constant, Kc, for this reaction is 53.3. H2(g) + I2(g) ⇌ 2HI(g) At this temperature, 0.400 mol of H2 and 0.400 mol of I2 were placed in a 1.00 L container to react. What concentration of HI is present at equilibrium?
Consider the following reaction:COCl2 (g) ⇌ CO (g) + Cl2 (g)A reaction mixture initially contains 1.6 M COCl 2. Determine the equilibrium concentration of CO if Kc for the reaction at this temperature is 8.33 x 10 -4. A) 4.2 x 10-4 MB) 1.5 x 10-3 MC) 3.7 x 10-2 MD) 2.1 x 10-2 ME) 1.3 x 10-3 M
A 5.0 L evacuated flask is charged with 2.0 moles of CO 2 and 1.5 moles of H 2 is allowed to come to equilibrium at 25 oC. If the equilibrium constant is 2.50, what is the equilibrium concentration of H2O?                               CO   2 (g)  +    H 2 (g)  ⇌  CO (g)  +  H 2O (g) 
A container initially contains [Br2] = 0.1 M and [I 2] = 0.2 M and undergoes the reaction:Br2 (g) + I 2 (g) ⇌ 2 BrI (g)     Kc = 1x10–10 at 25 °C:Calculate the equilibrium concentration of BrI(g).A) 1x10−3B) 3.5x 10−6C) 1.4x10−6D) 7.7 x 10−7E) 0.012 
At a certain temperature, the equilibrium constant K c for this reaction is 53.3.H2 + I 2 → 2 HIAt this temperature, 0.800 mol of H2 and .800 mol of I2 were placed in 1.00L container to react. What concentration of HI is present at equilibrium? 
At a certain temperature, the Kc of the reaction below is 1.5 x10 −11. If 0.10 mol N2 and 0.10 mol O2 are reacted together in a 1.00 L container, how much NO is present at equilibrium?N2 (g) + O2 (g) ⇌ 2 NO (g) Kc = 1.5x10−11A. 1.5x10−13 MB. 0.20 MC. 3.9x10−7 MD. 1.9x10−5 M
Carbon monoxide gas reacts with hydrogen gas at elevated temperatures to form methanol according to this equation.CO (g) + 2 H2 (g) ⇋ CH3OH (g)When 0.40 mol of CO and 0.30 mol of H 2 are allowed to reach equilibrium in a 1.0 L container, 0.060 mol of CH3OH are formed. What is the value of   Kc?a) 0.50b) 0.98c) 1.7d) 5.4 
Phosphorus pentachloride decomposes to phosphorus trichloride at high temperatures according to the equation: PCl5(g) ⇌ PCl3(g) + Cl2(g) At 250° 0.125 M PCl5 is added to the flask. If Kc = 1.80, what are the equilibrium concentrations of each gas?
The system described by the reactionCO(g) + Cl2(g) ⇌ COCl2(g)is at equilibrium at a given temperature when  PCO =0.31 atm , PCl2 = 0.11 atm , and PCOCl2 = 0.59 atm. An additional pressure of Cl2(g) = 0.38 atm is added.Find the pressure of CO when the system returns to equilibrium.
A 1.000 L vessel is filled with 2.000 moles of N 2, 1.000 mole of H2, and 2.000 moles of NH3. N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)When the reaction comes to equilibrium, it is observed that the concentration of H2 is 2.34 moles/L. What is the numerical value of the equilibrium constant Kc?
Consider the following reaction:Fe3+(aq) + SCN-(aq) ⇌ FeSCN2+(aq)A solution is made containing an initial [Fe3+] of 1.1 x 10-3M an initial [SCN-] of 7.8 x 10-4M. At equilibrium, [FeSCN2+] = 1.7 x 10-4M.A) Kc = 2.0 x 102B) Kc = 3 x 10-2C) Kc = 3.3 x 10-3D) Kc = 3.0 x 102E) Kc = 5.0 x 10-3
Practice: Consider the famous ammonia preparation3 H2(g) + N2(g) ⇌ 2 NH3(g)The equationK = [x]2 / [0.1 − 3x]3 [0.7 − x]is not a possible correct description of the equilibrium situation because
A 2.00 liter vessel is filled with NH 3 (g) to a pressure of 4.00 atm and the reactionN2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)comes to equilibrium at a fixed temperature. At equilibrium it is found that the pressure of H2 is 2.7 atm. What is the equilibrium pressure of NH3? 
The equilibrium constant for the reaction below at 25°C is 4.8 x 10 -6. Calculate the equilibrium concentration (mol/L) of Cl2 (g) if the initial concentration of ICI (g) is 1.33 mol/L. There is no I2 or Cl2 initially present. 2 ICI (g) ⇌ I2 (g) + Cl2 (g)a.) 2.9 x 10 -3b.) 5.8 x 10 -3c.) 3.2 x 10 -6d.) 6.4 x 10 -6e.) 343
What is the amount of "C" at equilibrium when 1 mole of A and 1 mole of B react according to the chemical reaction: 2 A + 2 B ⇌ C ?a. between 0 and 0.5 moleb. exactly 1 molec. between 0.5 and 2 molesd. exactly 2 molese. greater than two moles
If a 10.0 L vessel is charged with 0.482 mol N 2, 0.933 mol O2, calculate the concentration of each species at equilibrium.2 N2 + O2 ⇌ 2 N2O       Kc = 2.0 x 10 -32
At a certain temperature, the equilibrium constant,  Kc for this reaction is 53.3.H2(g) + I2(g) ⇌ 2HI(g)At this temperature, 0.300 mol of H2 and 0.300 mol of I2 were placed in a 1.00 L container to react. What concentration of HI is present at equilibrium? 
For the exothermic reactionPCl3(g) + Cl2(g) ⇌ PCl5(g)     Kp = 0.180 at a certain temperature.A flask is charged with 0.500 atm PCl3, 0.500 atm Cl2, and 0.300 atm PCl5 at this temperature.What are the equilibrium partial pressures of PCl 3, Cl2, and PCl5, respectively?Express your answers numerically in atmospheres with three digits after the decimal point, separated by commas.
Carbon disulfide is prepared by heating sulfur and charcoal. The chemical equation isS2(g) + C(s) → CS2(g)          Kc = 9.40 at 900 KHow many grams of CS2(g) can be prepared by heating 11.1 moles of S2(g) with excess carbon in a 7.00 L reaction vessel held at 900 K until equilibrium is attained?
For the reaction: H 2 (g) + Br 2 (g) ⇌ 2 HBr (g), K c = 7.5 × 10 2 at a certain temperature. If 2 mole each of H 2 and Br 2 are placed in 2-L flask, what is the concentration of H 2 at equilibrium?   A) 0.96      B) 0.93            C) 1.86            D) 0.04            E) 0.07
Consider the following reaction:SO2Cl2(g) ⇌ SO2(g) + Cl2(g)Kc = 2.99 × 10−7 at 227∘CIf a reaction mixture initially contains 0.177 M SO2Cl2, what is the equilibrium concentration of Cl 2 at 227∘C?
Consider this reactionAB3(g) ⇌ A(g) + 3B(g) What is the equilibrium constant expression if the intial concentration of  AB3 is 0.1 M and the equilibrium concentration of A is represented by x? Assume the intial concentrations of A and B are both zero. 
A flask is filled with 1.08 atm of oxygen gas and 0.88 atm of ammonia and the following reaction is allowed to come to equilibrium in the closed container.4 NH3 (g) + 5 O 2 (g) <==> 4 NO (g) + 6 H 2O (g)At equilibrium the pressure of O 2 is determined to be 0.38 atm. Calculate the pressure H 2O at equilibrium.A. 0.140 atmB. 0.840 atmC. 2.28 atmD. 0.456 atmE. 3.50 atm
A mixture consisting of 0.250 M N2(g) and 0.500 M H2 (g) reaches equilibrium according to the equation N2(g) + 3 H2(g) → 2 NH3(g)At equilibrium, the concentration of ammonia is 0.150M. Calculate the concentration of H2(g) at equilibrium. 1. 0.350 M2. 0.150 M3. 0.425 M4. 0.275 M5. 0.0750 M 
A mixture of 1.00 atm of NO, 0.50 atm of H 2, and 1.00 atm of N2 was allowed to reach equilibrium according to the reaction given below (initially there was no H2O). At equilibrium, the partial pressure of NO was found to be 0.62 atm. Determine the value of the equilibrium constant, Kp, for the reaction: 2NO(g) + 2H2(g) ⇌ N2(g) + 2H2O(g) a) 6.08 b) 31.0 c) 215.0 d) 26.5 e) 651.0
Consider the following reaction at 425 KBr2 (g) + Cl2 (g) ⇌ 2 BrCl (g)    Kc = 5.81If a 5.00 L reaction vessel in initially charged with 4.65 moles of Br  2 and 4.65 moles of Cl2, determine the concentration of Cl2 at equilibrium.A. 0.422 MB. 2.11 MC. 0.691 MD. 1.69 ME. 0.508 M
Assume that the change in concentration of N 2O4 is small enough to be neglected in the following problem.(a) Calculate the equilibrium concentration of both species in 1.00 L of a solution prepared from 0.129 mol of N2O4 with chloroform as the solvent.N2O4(g) ⇌ 2NO2(g)         Kc = 1.07 x 10−5 in chloroform
Consider the following reaction: 2NO(g) + Br2(g) ⇌ 2NOBr(g) Kp= 28.4 at 298 K In a reaction mixture at equilibrium, the partial pressure of NO is 107 torr and that of Br2 is 166 torr. What is the partial pressure of NOBr in this mixture?  
Assume that the change in concentration of COCl 2 is small enough to be neglected in the following problem.(a) Calculate the equilibrium concentration of all species in an equilibrium mixture that results from the decomposition of COCl2 with an initial concentration of 0.3166 M.COCl2(g) ⇌ CO(g) + Cl2(g)           K c = 2.2 × 10−10
Assume that the change in pressure of H 2S is small enough to be neglected in the following problem.(a) Calculate the equilibrium pressures of all species in an equilibrium mixture that results from the decomposition of H2S with an initial pressure of 0.824 atm.2H2S(g) ⇌ 2H2(g) + S2(g)               K P = 2.2 x 10 −6
Calculate the pressures of all species at equilibrium in a mixture of NOCl, NO, and Cl 2 produced when a sample of NOCl with a pressure of 10.0 atm comes to equilibrium according to this reaction:2NOCl(g) ⇌ 2NO(g) + Cl 2(g)          K P = 4.0 x 10−4
Phosphorus pentachloride decomposes according to the chemical equation. PCl5(g) ⇌ PCI3(g) + Cl2(g)             Kc = 1.80 at 250 °C A 0.250 mol sample of PCl5(g) is injected into an empty 2.50 L reaction vessel held at 250 °C. Calculate the concentrations of PCl5(g) and PCl3(g) at equilibrium.
A 0.010 M solution of the weak acid HA has an osmotic pressure (see chapter on solutions and colloids) of 0.293 atm at 25°C. A 0.010 M solution of the weak acid HB has an osmotic pressure of 0.345 atm under the same conditions.(a) Which acid has the larger equilibrium constant for ionization HA [HA(aq) ⇌ A−(aq) + H+(aq)] or HB [HB(aq) ⇌ H+(aq) + B−(aq)] ?
A 0.010 M solution of the weak acid HA has an osmotic pressure (see chapter on solutions and colloids) of 0.293 atm at 25°C. A 0.010 M solution of the weak acid HB has an osmotic pressure of 0.345 atm under the same conditions.HA [HA(aq) ⇌ A−(aq) + H+(aq)] or HB [HB(aq) ⇌ H+(aq) + B−(aq)] ?What are the equilibrium constants for the ionization of these acids?
The density of trifluoroacetic acid vapor was determined at 118.1 °C and 468.5 torr, and found to be 2.784 g/L. Calculate Kc for the association of the acid.
A 0.72-mol sample of PCl 5 is put into a 1.00-L vessel and heated. At equilibrium, the vessel contains 0.40 mol of PCl3(g) and 0.40 mol of Cl2(g). Calculate the value of the equilibrium constant for the decomposition of PCl5 to PCl3 and Cl2 at this temperature.
At 1 atm and 25 °C, NO2 with an initial concentration of 1.00 M is 3.3 × 10−3% decomposed into NO and O2. Calculate the value of the equilibrium constant for the reaction.2NO2(g) ⇌ 2NO(g) + O2(g)
Calculate the pressures of NO, Cl 2, and NOCl in an equilibrium mixture produced by the reaction of a starting mixture with 4.0 atm NO and 2.0 atm Cl2. (Hint: KP is small; assume the reverse reaction goes to completion then comes back to equilibrium.)2NO(g) + Cl2(g) ⇌ 2NOCl(g)             K P = 2.5 × 103
A student solved the following problem and found [N 2O4] = 0.16 M at equilibrium. How could this student recognize that the answer was wrong without reworking the problem? The problem was: What is the equilibrium concentration of N2O4 in a mixture formed from a sample of NO2 with a concentration of 0.10 M?2NO2(g) ⇌ N2O4(g)           K c = 160
What are all concentrations after a mixture that contains [H 2O] = 1.00 M and [Cl 2O] = 1.00 M comes to equilibrium at 25°C?H2O(g) + Cl2O(g) ⇌ 2HOCl(g)             K  c = 0.0900
Consider the reaction between H2 and O2 at 1000 K2H2(g) + O2(g) ⇌ 2H2O(g)   If 0.500 atm of H2 and 0.500 atm of O2 are allowed to come to equilibrium at this temperature, what are the partial pressures of the components?
What are the concentrations of PCl 5, PCl3, and Cl2 in an equilibrium mixture produced by the decomposition of a sample of pure PCl5 with [PCl5] = 2.00 M?PCl5(g) ⇌ PCl3(g) + Cl2(g)         K c = 0.0211
The hydrolysis of the sugar sucrose to the sugars glucose and fructose follows a first-order rate equation for the disappearance of sucrose.C12 H22 O11(aq) + H2 O(l) ⟶ C6 H12 O6(aq) + C6 H12 O6(aq)Rate = k[C12H22O11]In neutral solution, k = 2.1 × 10 −11/s at 27 °C. (As indicated by the rate constant, this is a very slow reaction. In the human body, the rate of this reaction is sped up by a type of catalyst called an enzyme.) (Note: That is not a mistake in the equation—the products of the reaction, glucose and fructose, have the same molecular formulas, C6H12O6, but differ in the arrangement of the atoms in their molecules). The equilibrium constant for the reaction is 1.36 × 105 at 27 °C. What are the concentrations of glucose, fructose, and sucrose after a 0.150 M aqueous solution of sucrose has reached equilibrium? Remember that the activity of a solvent (the effective concentration) is 1.
Liquid N2O3 is dark blue at low temperatures, but the color fades and becomes greenish at higher temperatures as the compound decomposes to NO and NO2. At 25 °C, a value of KP = 1.91 has been established for this decomposition. If 0.236 moles of N 2O3 are placed in a 1.52-L vessel at 25 °C, calculate the equilibrium partial pressures of N2O3(g), NO2(g), and NO(g).
Calculate the equilibrium concentrations of NO, O 2, and NO2 in a mixture at 250 °C that results from the reaction of 0.20 M NO and 0.10 M O2. (Hint: K is large; assume the reaction goes to completion then comes back to equilibrium.)2NO(g) + O2(g) ⇌ 2NO2(g)             K c = 2.3 × 10 5 at 250 °C
Calculate the equilibrium concentrations that result when 0.25 M O 2 and 1.0 M HCl react and come to equilibrium.4HCl(g) + O2(g) ⇌ 2Cl2(g) + 2H2 O(g)             K c = 3.1 × 1013
One of the important reactions in the formation of smog is represented by the equationO3(g) + NO(g) ⇌ NO2(g) + O2(g)                   K P = 6.0 × 1034What is the pressure of O3 remaining after a mixture of O3 with a pressure of 1.2 × 10 −8 atm and NO with a pressure of 1.2 × 10−8 atm comes to equilibrium? (Hint: KP is large; assume the reaction goes to completion then comes back to equilibrium.)
Assume that the change in concentration of N 2O4 is small enough to be neglected in the following problem.N2O4(g) ⇌ 2NO2(g)      Kc = 1.07 x 10−5 in chloroformShow that the change is small enough to be neglected.
In a 3.0-L vessel, the following equilibrium partial pressures are measured: N 2, 190 torr; H2, 317 torr; NH3, 1.00 × 103 torr. N2(g) + 3H2(g) ⇌ 2NH3(g)(b) Hydrogen is removed from the vessel until the partial pressure of nitrogen, at equilibrium, is 250 torr. Calculate the partial pressures of the other substances under the new conditions.
Assume that the change in concentration of COCl 2 is small enough to be neglected in the following problem.COCl2(g) ⇌ CO(g) + Cl2(g)           K c = 2.2 × 10−10Show that the change is small enough to be neglected.
Assume that the change in pressure of H 2S is small enough to be neglected in the following problem.2H2S(g) ⇌ 2H2(g) + S2(g)               K P = 2.2 x 10 −6Show that the change is small enough to be neglected.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Consider the equilibrium4NO2(g) + 6H2 O(g) ⇌ 4NH3(g) + 7O2(g)(d) If the change in the pressure of NO2 is 28 torr as a mixture of the four gases reaches equilibrium, how much will the pressure of O2 change?
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
A 1.00-L vessel at 400 °C contains the following equilibrium concentrations: N 2, 1.00 M; H2, 0.50 M; and NH3, 0.25 M. How many moles of hydrogen must be removed from the vessel to increase the concentration of nitrogen to 1.1 M?
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
Complete the changes in concentrations (or pressure, if requested) for the following reaction.
A Student ran the following reaction in the laboratory at 502 K PCl3(g) + Cl2(g) PCl_5(g)When she introduced 0.199 moles of PCI3(g) and 0.235 moles of Cl2(g) into a 1.00 liter container, she found the equilibrium concentration of Cl2(g) to be 6.84 times 10^-2 M. Calculate the equilibrium constant, Kc. she obtained for this reaction.
For the reaction H2(g) + CO2(g) <-->H2O(g) + CO(g) at 700C Kc = 0.534. Calculate the number of moles of H2 that are present at equilibrium if a mixture of 0.650 mole of CO and 0.650 mole of H2O is healed to 700 C in a 30.0-L container. 
A key step in the extraction of iron from its ore isFeO(s) + CO (g) ⇌ Fe (s) + CO2 (g) Kp = 0.403 at 1, 000°CThis step occurs in the 700°C to 1, 200°C zone within a blast furnace. What are the equilibrium partial pressures of CO(g) and CO2 (g) when 1.2200 atm of CO (g) and excess FeO(s) react in a sealed container at 1, 000°C?
At a certain temperature, the equilibrium Constant, Ko, for this reaction is 53.3. H2(g) + I2(g) ⇌ 2HI(g) Kc = 53.3 At this temperature, 0.300 mol of H2 and 0.300 mol of I2 were placed in a 1.00-L container to react. What concentration of HI s present at equilibrium? 
At a certain temperature, the Kp for the decomposition of H2S is 0.727. H2S (g) ⇌ H2 (g) + S (g) Initially, only H2S is present at a pressure of 0.165 atm in a closed container. What is the total pressure in the equilibrium?
Consider the following reaction: A (g) ⇌ B (g) + C (g) Find the equilibrium concentrations of A, B, and C for each of the following different values of Kc. Assume that the initial concentration of A in each case is 1.0 M and that the reaction mixture initially contains no products. Make any appropriate simplifying assumptions. Part BKc = 2.0 x 10-2 Express your answer using two significant figures. Enter your answers numerically separated by commas. 
The value of Kc for the reaction:N2O4 (g) ⇌ 2NO2 (g)is 0.53 at 461.5 K. Part 1 If a reaction vessel at that temperature initially contains 0.0251 MNO2 and 0.0251 MN2O4, what is the concentration of NO2 at equilibrium?Part 2What is the concentration of N2O4 at equilibrium?
Before any reaction occurs, the concentration of A In the reaction below is 0.0510 M. What is the equilibrium constant if the concentration of A at equilibrium is 0.0153 M? A (aq) ⇌ 2B (aq) + C (aq) Remember to use correct significant figures in your answer (round your answer to the nearest ten thousandth). Do not include units in your response.
At 200 °C, the equilibrium constant (Kp) for the reaction below is 2.40 x 10 3. 2NO (g) <-> N2 (g) + O2 (g) A closed vessel is initially charged with 36.1 atm of NO. At equilibrium, the partial pressure of O  2 is _____ atm. 
Enter your answer in the provided box.The equilibrium constant Kc for the equation 2H2 (g) + CO (g) ⇌ CH3OH (g) is 31 at a certain temperature. If there are 5.85 x 10-2 moles of H2 and 4.47 x 10-3 moles of CH3OH at equilibrium in a 7.63-L flask, what is the concentration of CO?
Nitrosyl bromide, NOBr, is formed in the reaction of nitric oxide, NO, with bromine, Br2 2NO(g) + Br2(g) --> 2NOBr(g) The reaction rapidly establishes equilibrium when the reactants are mixed. At a certain temperature the initial concentration of NO was 0.400 M and that of Br2 was 0.265 M. At equilibrium the concentration of NOBr was found to be 0.250 M. What is the value of Kc at this temperature. Express your answer numerically.
The equilibrium constant, Kc, for the following reaction is 7.00 x 10^-5 at 673 K.NH4I(s) NH3(g) + HI(g)Calculate the equilibrium concentration of HI when 0.411 moles of NH4I(s) are introduced into a 1.00 L vessel at 673 K.
Gaseous ammonia was introduced into a sealed container and heated to a certain temperature: 2 NH3(g) N2(g) + 3 H2(g) At equilibrium, [NH3] = 0.0237 M, [N2] = 0.115 M, and [H2] = 0.345 M. Calculate Kc for the reaction at this temperature.
The equilibrium constant Kc for the reaction:C ⇌ D + E is 8.10 x10-5. The initial composition of the reaction mixture is [C} = [D] = [E] =   1.10x10^3 M. What is the equilibrium concentration of C, D, and E?
A 0.682- g sample of ICl(g) is placed in a 625 - mL reaction vessel at 682 K. When equilibrium is reached between the ICl(g) and I2 (g) and Cl2(g) formed by its dissociation, 0.0383 g I2 (g) is present. What is KC for the reaction?
The equilibrium constant Kc for the reactionH2(g) + I2(g) ⇌ 2H1(g)is 54.3 at 430 C. At the start of the reaction, there are 0.714 mole of H_2, 0.984 mole of I2, and 0.886 mole of HI in a 2.40 L reaction chamber. Calculate the concentrations of the gases at equilibrium.
At a certain temperature, 0.720 mol of SO3 is placed in a 4.50-L container. 2SO3 (g) ⇌ 2SO2 (g) + O2 (g) At equilibrium, 0.110 mol of O2 is present. Calculate Kc. 
Calculate the value of the change in concentration from initial conditions to equilibrium ("x" in your ICE chart) for the products of the faollowing reaction:SO2(g) + NO2(g) ⇌ SO3(g) + NO(g)If the value of Kc for the reaction is 2.50 and the INITIAL concentrations of the reactants and products in the reaction mixture are 0.500 M SO2, 0.500 M NO2, 0.00500 M SO3, and 0.00500 M NO.
In a particular experiment, it was found that when O2(g) and CO(g) were mixed and allowed to react according to the equation:2CO(g) + O2(g) ⇌ 2CO2(g) the O2 concentration had decreased by 0.078 mol L-1 when the reaction reached equilibrium. How had the concentrations of CO and CO2 changed?The number of significant digits is set to 2; the tolerance is +/-1 in the 2nd significant digit.
Suppose a 500 mL flask is filled with 1.9 mol of H2 and 1.8 mol of I2. This reaction becomes possible: H2(g) + I2(g) ⇌ 2HI(g) Complete the table below, so that it lists the initial molarity of each compound, the change in molarity of each compound due to the reaction, and the equilibrium molarity of each compound after the reaction has come to equilibrium.Use x to stand for the unknown change in the molarity of H2. You can leave out the M symbol for molarity.
At a certain temperature, the equilibrium constant for the following chemical equation is 3.50. SO2(g) + NO2(g) ⇌ SO3(g) + NO(g) At this temperature, calculate the number of moles of NO2(g) that must be added to 2.52 mol of SO2(g) in order to form 1.20 mol of SO3(g) at equilibrium.
Be sure to answer all parts.The equilibrium constant Kc for the decomposition of phosgene, COCI2, is 4.63 x 10-3 at 527 °C: COCI2 (g) ⇋ CO (g) + CI2 (g) Calculate the equilibrium partial pressure of all the components, starting with pure phosgene at 0.560 atm. PCOCI2 = PCO = PCI2 =
At equilibrium, the concentrations in this system were found to be [N 2] = [O2] = 0.100 M and (NO) = 0.400 M. N2 (g) + O2 (g) ⇌ 2NO (g) If more NO is added, bringing its concentration to 0.700 M, what will the final concentration of NO be after equilibrium is re-established?
A mixture initially contains A, B, and C in the following concentrations: [A] = 0.350 M, [B] = 1.40 M, and [C] = 0.700 M. The following reaction occurs and equilibrium is established: A + 2B ⇌ C At equilibrium, [A] = 0.170 M and [C] = 0.880 M. Calculate the value of the equilibrium constant, Kc. Express your answer numerically.
Consider the following  unbalanced equation at some constant temperature: CO2 (g) ⇌ CO (g) + O2 (g)       K = 5.7 x 10-7 In an experiment, 4.9 mol of CO2 and 3.1 mol of CO are initially placed into a 1.0 L rigid container. Calculate the concentration of O2 when the reaction has reached equilibrium. Please use the correct number of significant figures when entering your answer and enter your answer using exponential format. For example 1.00 x 10-27 should be entered as 1.00E-27. 
At a certain temperature, the equilibrium constant, K, for this reaction is 53.3. H2 (s) + I2 (g) ⇌ 2HI (g)           K = 533 At this temperature, the reactants were placed in a container to react. If the partial pressures of H2 and I2 were each 0.700 bar initially, what is the partial pressure of HI at equilibrium?
Suppose a 500. mL flask is filled with 1.5 mol of H 2O, 0.20 mol of CO2 and 1.2 mol of H2. The following reaction becomes possible: CO (g) + H2O (g) ⇌ CO2 (g) + H2 (g) The equilibrium constant K for this reaction is 0.223 at the temperature of the flask. Calculate the equilibrium molarity of H2O.
At a certain temperature, 0.960 mol of SO3 is placed in a 4.50-L container. 2SO3(g) ⇌ 2SO2(g) + O2(g) At equilibrium, 0.110 mol of O2 is present. Calculate Kc. 
For the reaction H2 (g) + S (g) ⇌ H2S (g) the initial concentrations are 0.060 M H2, 0.080 MS, and no H2S. At equilibrium, [H] = 0.010 M. Part 1Calculate the concentrations of S and H2S at equilibrium. (Be sure to give your answers to three decimal places.) Part 2Calculate the value of K under the reaction conditions at equilibrium. (Be sure your answer has the appropriate number of significant figures.)
Suppose a 500. mL flask is filled with 2.0 mol of N2 and 1.5 mol of NH3. This reaction becomes possible: N2 (g) + 3H2 (g) ⇌ 2NH3 (g) Complete the table below, so that it lists the initial molarity of each compound, the change in molarity of each compound due to the reaction, and the equilibrium molarity of each compound after the reaction has come to equilibrium. Use x to stand for the unknown change in the molarity of N2. You can leave out the M symbol for molarity.
At a certain temperature, 0.920 mol of SO3 is placed in a 3.50-L container. 2SO3(g) ⇌ 2SO2(g) + O2(g) At equilibrium, 0.120 mol of O2 is present. Calculate Kc. 
Consider the reaction: N2(g) + O2(g) ⇌ 2 NO(g) for which Kc = 0.10 at 2,000°C. Starting with initial concentrations of 0.15 M N2 and 0.15 M O2, determine the equilibrium concentration of NO. a. 0.020 M b. 0.13 M c. 0.0071 M d. 0.014 M e. 0.041 M
For the reaction 2HI (g) <-> H2 (g) + I2 (g)      Keq = 0.016 Initially a container contains 0.60 M HI, 0.038 M H 2, and 0.15 M I 2 at equilibrium. What is the new equilibrium concentration of H2, if the H2 concentration is increased by 0.197 M?
The equilibrium constant, Kc, for the following reaction is 10.5 at 350 K. 2CH2Cl2 ⇌ CH4 (g) + CCl4 (g) Calculate the equilibrium concentrations of reactant and products when 0.357 moles of CH2Cl2 are introduced into a 1.00 L vessel at 350 K. [CH2Cl2] = __________ M [CH4] =  __________ M[CCl4] = __________  M
Enter your answer in the provided box. Hydrogen sulfide decomposes according to the following reaction, for which Kc = 9.30 x 10-8 at 700°C: 2H2S (g) ⇌ 2H2 (g) + S2 (g)If 0.49 mol of H2S is placed in a 3.0-L container, what is the equilibrium concentration of H2(g) at 700°C?
At a certain temperature, the equilibrium constant for the following chemical equation is 3.90. SO2 (g) + NO2 (g) ⇌ SO3 (g) + NO (g) At this temperature, calculate the number of moles of NO2(g) that must be added to 3.12 mol of SO2(g) in order to form 1.30 mol of SO3(g) at equilibrium.
At a certain temperature, 0.740 mol of SO3 is placed in a 3.00-L container. 2SO3(g)  ⇌ 2SO2(g) + O2(g)At equilibrium, 0.170 mol of O2 is present. Calculate Kc.
At a certain temperature, 0.740 mol of SO3 is placed in a 5.00-L container. 2SO3(g) ⇌ 2SO2(g) + O2(g) At equilibrium, 0.100 mol of O2 is present. Calculate Kc.
The equilibrium constant Kc = 1.1 x 10-2 for the following reaction at 400 K: PCl5 (g) ⇌ PCl3 (g) + Cl2 (g) (a) Given that 1.0 g of PCl5 was initially placed in a 250 ml reaction vessel, determine the molar concentrations in the mixture at equilibrium. (b) What percentage of PCl5 is decomposed at 400 K?
Consider the following reaction. A (aq) ⇌ 2B (aq)               K  c = 7.11 x 10 -6 at 500 Klf a 4.20 M sample of A is heated to 500 K, what is the concentration of B at equilibrium? 
During an experiment, 0.294 mol of H2 and 0.294 mol of I2 were placed into a 1.15 liter vessel where the reaction H2(g) + I2(g) ⇌ 2HI(g) came to equilibrium. For this reaction, Kc = 49.5 at the temperature of the experiment. What were the equilibrium concentrations of H2, I2, and HI? 
Consider the following reaction. A (aq) ⇌ 2B (aq)      K c = 4.70 x 10 -6 at 500 K If a 4.10 M sample of A is heated to 500 K, what is the concentration of B at equilibrium? 
Enter your answer in the provided box. Even at high temperatures, the formation of NO is not favored: (Kc = 4.10 x 10-4 at 2,000°C) N2 (g) + O2 (g) ⇌ 2NO (g) What is [NO] when a mixture of 0.20 mol of N2(g) and 0.22 mol of O2(g) reach equilibrium in a 1.0-L container at 2,000 °C?
Carbon disulfide is prepared by heating sulfur and charcoal. The chemical equation isS2 (g) + C (s) ⇌ CS2 (g)      Kc = 9.40 at 900 K How many grams of CS2(g) can be prepared by heating 20.5 moles of S2(g) with excess carbon in a 8.40 L reaction vessel held at 900 K until equilibrium is attained?
5.00 mol of solid A placed in a seated 1.00-L container and allowed to decompose in gaseous B and C. The concentration of B increased until it reached 1.40 M, remained constant. A (s) ⇌ B (g) + C (g) Then, the container volume was doubled and equilibrium was re-established. How many moles of A remain?
Be sure to answer all parts.The equilibrium constant Kc for the reaction H2 (g) + Br2 (g) ⇋ 2HBr (g) is 2.180 x 106 at 730°C. Starting with 2.20 moles of HBr in a 21.6-L reaction vessel, calculate the concentrations of H2, Br2 and HBr at equilibrium. 
Phosphorus pentachloride decomposes according to the chemical equation PCl5 (g) ⇌ PCl3 (g) + Cl2(g)                 K c = 1.80 at 250 °C.A 0.162 mol sample of PCl5 (g) is injected into an empty 2.10 L reaction vessel held at 250 °C. Calculate the concentrations of PCl5 (g) and PCl3 (g) at equilibrium. 
Consider the following reaction. 2A(g) ⇌ B(g)    Kp = 2.42 x 10 -5 at 500 KIf a sample of A(g) at 3.50 bar is heated to 500 K, what is the pressure of B(g) at equilibrium?PB = 
Carbon disulfide is prepared by heating sulfur and charcoal. The chemical equation is S2 (g) + C (s) ⇌ CS2 (g)       Kc = 9.40 at 900 K How many grams of CS2 (g) can be prepared by heating 13.0 moles of S2 (g) with excess carbon in a 5.85L reaction vessel held at 900 K until equilibrium is attained?
At 25 °C, the equilibrium constant Kc = 65 for the reaction 2A (aq) = B (aq) + C (aq) at 298K. If 2.50 mol of A is added to enough water to prepare 1.00 L of solution, what will the equilibrium concentration of A be? a. 0.15 M b. 1.18 M c. 0.68 M d. 0.24 M
Carbon disulfide is prepared by heating sulfur and charcoal. The chemical equation is S2 (g) + C (s) ⇌ CS2 (g)        K c = 9.40 at 900 K How many grams of CS 2(g) can be prepared by heating 13.5 moles of S 2(g) with excess carbon in a 5.95 L reaction vessel held at 900 K until equilibrium is attained?
Consider the following reaction. A (aq) ⇌ 3B (aq)         Kc = 6.84 x 10-6  at 500 K If a 1.60 M sample of A is heated to 500 K, what is the concentration of B at equilibrium?
Consider the fllowing reaction. A(aq) ⇌ 2B(aq)             Kc = 3.16 x 10-6 at 500 KIf a 2.80 M sample of A is heated to 500 K, what is the concentration of B at equilibrium? 
At a certain temperature, the Kp for the decomposition of H2S is 0.818. H2S (g) ⇌ H2 (g) + S (g) Initially, only HS is present at a pressure of 0.213 atm in a closed container. What is the total pressure in the container at equilibrium?
At a certain temperature, 0.326 m of CH 4 and 0.941 mol of H2O is placed in a 2.50 L container. CH4(g) + 2H2O(g) ⇌ CO2(g) + 4H2(g) At equilibrium, 5.28 g of CO2 is present. Calculate Kc. 
A mixture of 0.440 M H 2O, 0.310 M Cl2O, and 0.653 M HCIO are enclosed in a vessel at 25°C. H2O(g) + Cl2O(g) ⇌ 2HOCl(g)            K c = 0.090 at 25°C Calculate the equilibrium concentrations of each gas at 25°C.
At a particular temperature, 8.0 mol NO2 is placed into a 1.0-L container and the NO2 dissociates by the reaction. At equilibrium the concentration of NO(g) is 2.0 M. Calculate K for this reaction. K = _______
At equilibrium, the concentrations in this system were found to be [N2] = [O2] = 0.200 M and [NO] = 0.400 M. N2 (g) + O2 (g) ⇌ 2NO(g) If more NO is added, bringing its concentration to 0.700 M, what will the final concentration of NO be after equilibrium is re-established?
At a certain temperature, the Kp for the decomposition of H2S is 0.721. H2S(g) ⇌ H2(g) + S(g)Initially, only H2S is present at a pressure of 0.139 atm in a closed container. What is the total pressure in the container at equilibrium? 
The equilibrium constant Kc = 49 for the reaction: PCl3 (g) + Cl2 (g) = PCl5 (g) at 230 °C. If 0.70 mol of PCl3 is added to 0.70 mol of Cl2 in a 1.00-L reaction vessel at 230 °C, what is the concentration of PCl3 when equilibrium has been established? a. 0.59 M b. 0.30 M c. 0.11 M d. 0.83 M
Before any reaction occurs, the concentration of A in the reaction below is 0.049 M. What is the equilibrium constant if the concentration of A at equilibrium is 0.0196 M? A(g) ⇌ B (g) + 2C (g)
At a certain temperature, 0.3811 mol of N2 and 1.641 mol of H2 are placed in a 3.00-L container. N2 (g) + 3H2 (g) ⇌ 2NH3 (g) At equilibrium, 0.1001 mol of N2 is present. Calculate the equilibrium constant, Kc.
1.0 mol each of H2, I2, and HI are placed in a 2.0L reaction vessel at 1200K. Kc for the reaction H2(g) + I2(g) ⇌ 2Hl(g) is 4.6 at the given temperature. What is the equilibrium concentration of HI?
Part BThe following reaction was performed in a sealed vessel at 751°C: H2 (g) + I2 (g) ⇌ 2HI (g) Initially, only H2 and I2 were present at concentrations of [H2] = 3.35 M and [I2] = 2.35M. The equilibrium concentration of I2 is 0.0600 M. What is the equilibrium constant. Kc, for the reaction at this temperature? Express your answer numerically.
Calculate the equilibrium concentrations of N2O4 and NO2 at 25°C in a vessel that contains an initial N2O4 concentration of 0.0376 M The equilibrium constant Kc for the reaction N2O4(g) ⇌ 2NO2(g) is 4.64 x 10-3 at 25°C.
Phosphorus pentachloride decomposes according to the chemical equation PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)    Kc = 1.80 at 250°C A 0.179 mol sample of PCI5(g) is injected into an empty 2.50 L reaction vessel held at 250°C. Calculate the concentrations of PCl5(g) and PCl3(g) at equilibrium.
At a certain temperature, the Kp for the decomposition of H2S is 0.821. H2S (g) ⇌ H2 (g) + S (g) Initially, only H2S is present at a pressure of 0.270 atm in a closed container. What is the total pressure in the container at equilibrium?
When 1.00 mol of A and 0.800 mol of B are placed in a 2.00 L container and allowed to come to equilibrium, the resulting mixture is found to be 0.20M in D. What is the value of K at equilibrium? (This problem requires extra step of using quantity and volume to convert to molarity. Here I'm giving you moles: in lab you might instead be starting with grams, and needing to convert grams to moles, then moles to molarity.)
At a certain temperature, the Kp for the decomposition of H2S is 0.859. H2S (g) ⇌ H2 (g) + S (g) Initially, only H2S is present at a pressure of 0.145 atm in a closed container. What is the total pressure in the container at equilibrium?
Consider the following reaction. 2A(g) ⇌ B(g)    Kp = 4.84 x 10 -5 at 500 KIf a sample of A(g) at 1.90 atm is heated to 500 K, what is the pressure of B(g) at equilibrium?PB = 
When HNO2 is dissolved in water it partially dissociates according to the equation HNO2 ⇌ H+ + NO2-. A solution is prepared that contains 3.000 g of HNO2 in 1.000 kg of water. Its freezing point is found to be -0.1281°C Calculate the fraction of HNO2 that has dissociated. Express your answer using two significant figures. 
Calculate the equilibrium concentrations of H2, I2 and HI at 500K. The equilibrium constant Kc at 500K for the reaction H2(g) + I2(g) ⇌ 2HI(g) is 129.
At a certain temperature, the K for the decomposition of H2S is 0.812. H2S (g) ⇌ H2 (g) + S (g) Initally, only H2S is present at a pressure of 0.237 bar in a closed container. What is the total pressure in the container at equilibrium?
Be sure to answer all parts.The equilibrium constant Kc for the reaction below is 0.00209 at a certain temperature. Br2 (g) ⇌ 2Br (g) If the initial concentrations are [Br2] = 0.0335 M and [Br] = 0.0617 M, calculate the concentrations of these species at equilibrium. [Br2] = [Br] = 
At 473 K, for the elementary reaction 2NOCl (g) k1k-1⇌ 2NO (g) + Cl2 (g)k1 = -7.8 x 10-2 L/mols and k-1 = 4.7 × 102 L2/mol2sA sample of NOCl is placed in a container and heated to 473 K. When the system comes to equilibrium, [NOCI] is found to be 0.60 mol/L.Part AFind the concentration of NO.Express your answer to two significant figures and include the appropriate units. Part B Find the concentration of Cl2. Express your answer to two significant figures and include the appropriate units.
Using the Equilibrium constant The reversible chemical reaction A + B ⇌ C + D has the following equilibrium constant. Kc = [C][D]/[A][B] = 2.7 Part A Initially, only A and B are present, each at 2.00 M. What is the final concentration of A once equilibrium is reached?Express the molar concentration numerically using two significant figures.
Phosphorus pentachloride decomposes according to the chemical equation PCI5(g) ⇌ PCI3(g) + Cl2(g)         Kc = 1.80 at 250°C A 0.250 mol sample of PCI5(g) is injected into an empty 2.90 L reaction vessel held at 250°C. Calculate the concentrations of PCl5(g) and PCl3(g) at equilibrium. [PCl5] = [PCl3] =
At some temperature, 0.765 moles of NO(g) and 0.400 moles of O2(g) are introduced into a 1.00 L reaction vessel and allowed to come to equilibrium according to the following equation:2NO(g) + O2(g) → 2 NO2(g) At equilibrium, there are 0.725 moles of NO2(g) formed. What is the value of Kc? 
2.0 mol each of PCl5, PCl3, and Cl2 are placed in a 2.0L reaction vessel at 620K. Kc for the reaction PCl5(g) ⇌ PCl3(g) + Cl2(g) is 0.60 at the given temperature. What is the equilibrium concentration of Cl2?
At a certain temperature, the equilibrium constant for the following chemical equation is 3.80. SO2 (g) + NO2 (g) ⇌ SO3 (g) + NO (g) At this temperature, calculate the number of moles of NO 2 (g) that must be added to 2.76 mol of SO2 (g) in order to form 1.20 mol of SO 3 (g) at equilibrium.
At a certain temperature, 0.4611 mol of N2 and 1.541 mol of H2 are placed in a 3.00-L container.At equilibrium, 0.1201 mol of N2 is present. Calculate the equilibrium constant, Kc.
In a study of the formation of NOx air pollution, a chamber heated to 2200°C was filled with air (0.790 atm N2, 0.210 atm O2). What are the equilibrium partial pressures of N2, O2, and NO if Kp = 0.0500 for the following reaction: N2 (g)+ O2 (g) ⇌ 2NO (g) 
At a certain temperature, the Kp for the decomposition of H2S is 0.782. H2S (g) ⇌ H2 (g) + S (g) Initially, only H2S is present at a pressure of 0.183 atm in a closed container. What is the total pressure in the container at equilibrium?
At a certain temperature, O.960 mol of SO3 is placed in a 3.00-L container. 2SO3 (g) ⇌ 2SO2 (g) + O2 (g) At equilibrium, 0.130 mol of O2 is present. Calculate Kc. 
At a certain temperature, the equilibrium constant, Kc, for this reaction is 53.3. H2 (g) + I2 (g) ⇌ 2HI (g)             Kc = 53.3 At this temperature, 0.400 mol of H2 and 0.400 mol of I2 were placed in a 1.00 - L container to react. What concentration of HI is present at equilibrium?
A mixture of 0.500 mole of carbon monoxide and 0.400 mole of bromine was placed into a rigid 1.00-L container and the system was allowed to come to equilibrium. The equilibrium concentration of COBr2 was 0.233 M. What is the value of Kc for this reaction? CO (g) + Br2 (g) = COBr2 (g) a. 2.3 b. 5.23 c. 1.16 d. 1.22
A 4.0L reaction flask initially contains 4.0 mol of SO3 at 400K. Sulfur dioxide and oxygen form: 2SO3(g) ⇌ 2SO2(g) + O2(g)After equilibrium is established, 0.27 mol SO3 remain. What is the value of Kc?
Consider the following reaction. A (aq) ⇌ 2B (aq)   Kc = 9.53 x 10-6 at 500 K If a 4.00 M sample of A is heated to 500 K, what is the concentration of B at equilibrium?
For the reaction in the previous problem, that is 2HI (g) <-> H2 (g) + I2(g)        Keq = 0.016 Initially a container contains 0.37 M HI and no product What is the equilibrium concentration of H 2? 
The value of Kc for the thermal decomposition of hydrogen sulfide, shown below, is 2.2 x 10-4 at 1400 K.2H2S (g) → 2H2 (g) + S2 (g) A sample of gas in which [H2S] = 3.05 M is heated to 1400 K in a sealed vessel. After chemical equilibrium has been achieved, what is the value of [H2S]? Assume no H2 or S2 was present in the original sample.
0.6 mol of X is placed in an empty 1.00 L flask and the temperature is raised to 282°C. The following reaction takes place: X (g) ⇌ Y (g) + 3Z (g) At equilibrium, the [Y] = 0.06 M. Determine the equilibrium constant, K, at 282°C. Enter your answer to 3 significant figures and enter a number in scientific notation enter 1 x 10-3 as 1E-3).
Consider the reaction C(s) + CO2(g) ⇌ 2CO(g). When 1.56 mol of CO2 and an excess of solid carbon are heated in a 22.0 L container at 1100K, the equilibrium concentration of CO is 6.74 x 10-2 M. What is the equilibrium concentration of CO2? What is the value of the equilibrium constant Kc at 1100 K?
In air at 25°C and 1.00 atm, the N2 concentration is 0.01 M and the O2 concentration is 0.033 M. The reactionN2(g) + O2(g) ⇌ 2N0(g) has Kc = 4.8 x 10-31 at 25°C.Taking the N2 and O2 concentrations given above as initial values, calculate the equilibrium NO concentration that should exist in our atmosphere from this reaction at 36°C, Kc = 6.4E-30. Make simplifying assumptions in your calculations. (Express your answer in scientific notation.) 
At equilibrium, the concentrations in this system were found to be [N 2] = [O2] = 0.100 M and [NO] = 0.500 M. N2(g) + O2(g) ⇌ 2NO(g) If more NO is added, bringing its concentration to 0.800 M, what will the final concentration of NO be after equilibrium is re-established?
If a solution with initial concentrations of PCl 3 and Cl2 both equaling 2.50 x 10 -3 M before reaction gives an equilibrium concentration of PCl3 of 5.25 x 10 -4 M. What is the equilibrium constant for the reaction? PCl5 <-> PCl3 + Cl2
At a certain temperature, 0.4811 mol of N2 and 1.581 mol of H2 are placed in a 4.00-L container. N2 (g) + 3H2 (g) ⇌  2NH3 (g) At equilibrium, 0.1401 mol of N2 is present. Calculate the equilibrium constant, Kc.
Carbon disulfide is prepared by heating sulfur and charcoal. The chemical equation is S2(g) + C(s) ⇌ CS2(g)          Kc = 9.40 at 900 K How many grams of CS2(g) can be prepared by heating 10.5 moles of S2(g) with excess carbon in a 5.10 L reaction vessel held at 900 K until equilibrium is attained? 
At a certain temperature, 0.4811 mol of N2 and 1.601 mol of H2 are placed in a 2.00-L container. N2 (g) + 3H2 (g) ⇌ 2NH3 (g) At equilibrium, 0.1201 mol of N2 is present. Calculate the equilibrium constant, Kc. 
At a certain temperature, the equilibrium constant  K for the following reaction is 225:N2(g) + O2(g) ⇌ 2NO(g) Use this information to complete the following table. 
Initially, 0.680 mol of A is present in a 4.00-L solution. 2A (aq) ⇌ 2B (aq) + C (aq) At equilibrium, 0.200 mol of C is present. Calculate K.
A reaction vessel at 27 °C contains a mixture of SO2 (P = 3.10 atm) and O2 (P = 1.10 atm). When a catalyst is added the reaction 2SO2 (g) + O2 (g) ⇌ 2SO3 (g) takes place. At equilibrium the total pressure is 3.95 atm. Find the value of Kc. Express your answer using two significant figures.
The reaction CO2 (g) + C (s) ⇌ 2CO (g) has Kp = 5.78 at 1200 K. Part ACalculate the total pressure at equilibrium when 4.62 g of CO2 is introduced into a 10.0-L container and heated to 1200 K in the presence of 3.73 g of graphite. Express your answer to three significant figures and include the appropriate units. 
An equilibrium mixture contains 0.700 mol of each of the products (carbon dioxide and hydrogen gas) and 0.200 mol of each of the reactants (carbon monoxide and water vapor) in a 1.00-L container. CO (g) + H2O (g) ⇌ CO2 (g) + H2 (g) How many moles of carbon dioxide would have to be added at constant temperature and volume to increase the amount of carbon monoxide to 0.300 mol once equilibrium has been reestablished?
At 100°C, Kc = 4.72 for the reaction 2NO2(g) ⇌ N2O4(g). An empty 10.0 L flask is filled with 9.20 g of NO2 at 100°C. What is the total pressure in the flask at equilibrium?
For the reaction, 2 A(g) ⇌ B(g) + 2 C(g), a reaction vessel initially contains only A at a pressure of PA = 264 mmHg. At equilibrium, PA = 66 mmHg. Calculate the value of K_p. (Assume no changes in volume or temperature.) Express your answer using two significant figures. 
At 25°C, the reaction 2NH3(g) ⇌ N2(g) + 3H2(g) has Kc = 2.3 x 10-9. If 0.058 mol NH3 is placed in a 2.06 L container, what will the concentrations of N2 and H2 be when equilibrium is established? Make simplifying assumptions in your calculations. Assume the change in NH3 concentration is insignificant if compared to initial value. 
Consider the formation of hydrogen fluoride: H2 (g) + F2 (g) <-> 2HF (g) If a 3.0 L nickel reaction container (glass cannot be used because it reacts with HF) filled with 0.0055 M H2 is connected to a 3.4 L container filled with 0.033 M F 2. The equilibrium constant. Kp, is 7.8 x 1014. Calculate the molar concentration of HF at equilibrium. 
Be sure to answer all parts. The water-gas shift reaction plays a central role in the chemical methods for obtaining cleaner fuels from coal: CO (g) + H2O (g) ⇌ CO2 (g) + H2 (g) A study was made in which equilibrium was reached with [CO] = [H2O] = [H2] = 0.100 M and [CO2] = 0.400 M. After 1.15 mol of H2 is added to the 2.00-L container and equilibrium is reestablished, what are the new concentrations of all the components? 
The value of Kc for the thermal decomposition of hydrogen sulfide, shown below, is 2.2 x 10-4 at 1400 K.2H2S(g) ⇌ 2H2(g) + S2(g)A sample of gas in which [H2S] = 5.20 M is heated to 1400 K in a sealed vessel. After chemical equilibrium has been achieved, what is the value of [H2S]? Assume no H2 or S2 was present in the original sample.
A mixture of 0.1000 mol of CO2, 0.1000 mol of H2, and 0.1000 mol of H2O is placed into a 2.000-L vessel. The following equilibrium is established: CO2(g) + H2(g) ⇌ CO(g) + H2O(g) At equilibrium, [CO2] = 0.00954 M. Calculate the equilibrium concentrations of H2, CO, H2O, and the equilibrium constant for the reaction.