Chemistry Chemistry Practice Problems Solutions Library

Thermochemical Equation Solutions Library

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105 solutions

Thermochemical Equation

Q. For the following reaction, what is ∆H° when 25.0 g of Na2O2(molar mass = 77.98 g mol−1) is reacted with water?2 Na2O2(s) + 2 H2O(l) → 4 NaOH(s) + ...

Solved • Nov 29, 2019

Thermochemical Equation

Q. For the reactionH2(g) + 1/2O2(g) --> H2O(l)              deltaH = –286 kJ/molcalculate the enthalpy change when 2.66 g of water is produced.1. 7...

Solved • Nov 21, 2019

Thermochemical Equation

Q. How much energy (kJ) is required to vaporize 158 g of butane (C4H10) at its boiling point, if Δvap is 24.3 kJ/mole?(a) 15.1 kJ(b) 66.1 kJ(c) 89.4 k...

Solved • Nov 1, 2019

Thermochemical Equation

Q. How much energy is evolved during the reaction of 51.2 g of Al, according to the reaction below?Assume that there is excess Fe2O3.Fe2O3(s) + 2 Al(s...

Solved • Oct 25, 2019

Thermochemical Equation

Q. Given the thermochemical equation: 4 Fe(s) + 3 O2(g) ⟶ 2 Fe2O3(s)         ΔHrxn = –1652 kJ mol–1 What is the ΔH for the reaction when 500.0 g of Fe...

Solved • Oct 4, 2019

Thermochemical Equation

Q. For the reaction, CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (l), ΔH = -890 kJ, what will be the change in enthalpy when 3 moles of methane reacts in exces...

Solved • Aug 27, 2019

Thermochemical Equation

Q. In a constant-pressure calorimeter, 70.0 mL of 0.320 M Ba(OH) 2 was added to 70.0 mL of 0.640 M HCl. The reaction caused the temperature of the sol...

Solved • Aug 7, 2019

Thermochemical Equation

Q. The addition of hydrochloric acid to a silver nitrate solution precipitates silver chloride according to the reaction:AgNO3(aq) + HCl(aq) → AgCl(s)...

Solved • Nov 12, 2018

Thermochemical Equation

Q. What mass of natural gas (CH4) must you burn to emit 268 kJ of heat?CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)             Hrxno= –802.3 kJ/mol

Solved • Nov 12, 2018

Thermochemical Equation

Q. Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin plastic divider. When ...

Solved • Nov 12, 2018

Thermochemical Equation

Q. Hydrogen gas reacts with oxygen to form water.2 H2(g) + O2(g) → 2 H2O(g)         ΔH = –483.5 kJ/molDetermine the minimum mass of hydrogen gas requi...

Solved • Nov 12, 2018

Thermochemical Equation

Q. Manganese reacts with hydrochloric acid to produce manganese(II) chloride and hydrogen gas.Mn(s) + 2 HCl(aq) → MnCl2(aq) + H2(g)When 0.630 g Mn is ...

Solved • Nov 12, 2018

Thermochemical Equation

Q. Natural gas burns in air to form carbon dioxide and water, releasing heat.CH4(g) + O2(g) → CO2(g) + H2O(g); ΔHrxn˚ = –802.3 kJ/molWhat minimum mass...

Solved • Nov 12, 2018

Thermochemical Equation

Q. Find ΔH for the combustion of ethanol (C2H6O) to carbon dioxide and liquid water from the following data. The heat capacity of the bomb calorimeter...

Solved • Nov 12, 2018

Thermochemical Equation

Q. Nitromethane (CH3NO2) burns in air to produce significant amounts of heat: 2 CH3NO2(l) + 3/2 O2(g) → 2 CO2(g) + 3 H2O(l) + N2(g); ΔH˚rxn = -1418 kJ...

Solved • Nov 12, 2018

Thermochemical Equation

Q. Titanium reacts with iodine to form titanium(III) iodide, emitting heat, via the following reaction: 2 Ti(s) + 3 I2(g) → 2 TiI3(s); ΔH˚rxn= -839 kJ...

Solved • Nov 12, 2018

Thermochemical Equation

Q. Natural gas is very abundant in many Middle Eastern oil fields. However, the costs of shipping the gas to markets in other parts of the world are h...

Solved • Oct 31, 2018

Thermochemical Equation

Q. A pound of plain M&M candies contains 96 g fat, 320 g carbohydrate, and 21 g protein.Table 5.5: Compositions and Fuel ValuesFuelValuekcal/g(Cal...

Solved • Oct 31, 2018

Thermochemical Equation

Q. The heat of combustion of fructose, C6 H12 O6, is -2812 kJ/mol.If a fresh golden delicious apple weighing 4.26 oz (121 g ) contains 17.0 g of fruct...

Solved • Oct 31, 2018

Thermochemical Equation

Q. The automobile fuel called E85 consists of 85% ethanol and 15% gasoline. E85 can be used in so-called flex-fuel vehicles (FFVs), which can use gaso...

Solved • Oct 31, 2018

Thermochemical Equation

Q. Ozone, O3(g), is a form of elemental oxygen that is important in the absorption of ultraviolet radiation in the stratosphere. It decomposes to O2(g...

Solved • Oct 31, 2018

Thermochemical Equation

Q. A sample of a hydrocarbon is combusted completely in O2(g) to produce 24.01 g CO2(g), 4.917 g H2O(g), and 342 kJ of heat.Calculate the valu...

Solved • Oct 31, 2018

Thermochemical Equation

Q. Ethanol (C2H5OH) is currently blended with gasoline as an automobile fuel.Calculate the heat produced per liter of ethanol by combustion of ethanol...

Solved • Oct 31, 2018

Thermochemical Equation

Q. Methanol (CH3OH) is used as a fuel in race cars.You may want to reference (Pages 187 - 190) Section 5.7 while completing this problem.Write a balan...

Solved • Oct 31, 2018

Thermochemical Equation

Q. Under constant-volume conditions the heat of combustion of glucose (C6H12O6) is 15.57 kJ/g. A 3.550 -g sample of glucose is burned in a bomb calori...

Solved • Oct 31, 2018

Thermochemical Equation

Q. The enthalpy of neutralization for the reaction of a strong acid with a strong base is 256 kJ/mol water produced. How much energy will be released ...

Solved • Oct 18, 2018

Thermochemical Equation

Q. Consider the dissolution of CaCl2:CaCl2 (s) → Ca2+(aq) + 2 Cl- (aq)          ΔH = -81.5 kJ An 11.0-g sample of CaCl2 is dissolved in 125 g water, w...

Solved • Oct 18, 2018

Thermochemical Equation

Q. Consider the combustion of propane:C3H8 + 5O2 → 3CO2 + 4H2O           ΔH = -2221 kJAssume that all the heat in Example 7‑3 comes from the combustio...

Solved • Oct 17, 2018

Thermochemical Equation

Q. The enthalpy of combustion of hard coal averages −35 kJ/g, that of gasoline, 1.28 x 105 kJ/gal. How many kilograms of hard coal provide the same am...

Solved • Oct 16, 2018

Thermochemical Equation

Q. When 2.50 g of methane burns in oxygen, 125 kJ of heat is produced. What is the enthalpy of combustion per mole of methane under these conditions?

Solved • Oct 16, 2018

Thermochemical Equation

Q. What mass of carbon monoxide must be burned to produce 175 kJ of heat under standard state conditions?

Solved • Oct 16, 2018

Thermochemical Equation

Q. How much heat is produced by combustion of 125 g of methanol under standard state conditions?

Solved • Oct 16, 2018

Thermochemical Equation

Q. The addition of 3.15 g of Ba(OH) 2∙8H2O to a solution of 1.52 g of NH 4SCN in 100 g of water in a calorimeter caused the temperature to fall by 3.1...

Solved • Oct 16, 2018

Thermochemical Equation

Q. Dissolving 3.0 g of CaCl2(s) in 150.0 g of water in a calorimeter (Figure 5.12) at 22.4°C causes the temperature to rise to 25.8°C. What is the app...

Solved • Oct 16, 2018

Thermochemical Equation

Q. A 0.500 g sample of KCl is added to 50.0 g of water in a calorimeter (Figure 5.12). If the temperature decreases by 1.05°C, what is the approximate...

Solved • Oct 16, 2018

Thermochemical Equation

Q. Silver bromide is used to coat ordinary black-and-white photographic film, while high-speed film uses silver iodide.(a) When 50.0 mL of 5.0 g/L AgN...

Solved • Oct 16, 2018

Thermochemical Equation

Q. Three of the reactions that occur when the paraffin of a candle (typical formula C21H44) burns are as follows:(1) Complete combustion forms CO2 and...

Solved • Oct 15, 2018

Thermochemical Equation

Q. Diluting sulfuric acid with water is highly exothermic:H2SO4(l)     H2O ⟶ H2SO4(aq) + heatSuppose you carry out the dilution in a calorimeter. The ...

Solved • Oct 15, 2018

Thermochemical Equation

Q. Compounds of boron and hydrogen are remarkable for their unusual bonding and also for their reactivity. With the more reactive halogens, for exampl...

Solved • Oct 15, 2018

Thermochemical Equation

Q. A chemical engineer burned 1.520 g of a hydrocarbon in the bomb of a calorimeter (see Figure 6.10). The water temperature rose from 20.00°C to 23.5...

Solved • Oct 15, 2018

Thermochemical Equation

Q. When a 2.150-g sample of glucose, C6H12O6, is burned in a bomb calorimeter with a heat capacity of 6.317 kJ/K, the temperature of the calorimeter i...

Solved • Oct 15, 2018

Thermochemical Equation

Q. A chemist measures the energy change ΔH during the following reaction: CH4 (g)+2O2 (g) → CO2 (g) + 2H2O (l)     ΔH = -882. kJUse the information to...

Solved • Oct 5, 2018

Thermochemical Equation

Q. The following thermochemical equation is for the reaction of bromine trifluoride(g) to form bromine(g) and fluorine(g). 2BrF3 (g) → Br2 (g) + 3F2 (...

Solved • Jul 18, 2018

Thermochemical Equation

Q. The reaction of cyanamide, NH2CN(s), with oxygen was run in a bomb calorimeter, and ΔE was found to be -742.7 kJ/mol of NH2CN(s) at 298 K. Calculat...

Solved • Jul 17, 2018

Thermochemical Equation

Q. How much heat energy is required to boil 30.5 g of ammonia, NH3? The molar heat of vaporization of ammonia is 23.4 kJ/mol. 

Solved • Jul 16, 2018

Thermochemical Equation

Q. Enter your answer in the provided box.Liquid methanol (CH3OH) can be used as an alternative fuel in pickup and SUV engines. An industrial method fo...

Solved • Jul 9, 2018

Thermochemical Equation

Q. Be sure to answer all parts.Stearic acid (C18H36O2) is a typical fatty acid, a molecule with a long hydrocarbon chain and an organic acid group (CO...

Solved • Jul 9, 2018

Thermochemical Equation

Q. When a 5.00-g sample of KCI is dissolved in water in a calorimeter that has a total heat capacity of 2.683 kJ • K-1, the temperature decreases by 0...

Solved • Jul 4, 2018

Thermochemical Equation

Q. When a 2.050 gram sample of methanol (CH3OH) was burned in air, it released 40.81 kilojoules (kJ) of heat. Calculate the enthalpy change for the co...

Solved • Jun 19, 2018

Thermochemical Equation

Q. The oxidation of copper (l) oxide, Cu 2O(s), to copper(II) oxide, CuO(s), is an exothermic process, 2Cu2O(s) + O2(g) → 4CuO(s)                    Δ...

Solved • Jun 6, 2018

Thermochemical Equation

Q. When solutions containing silver ions and chloride ions are mixed, silver chloride precipitates: Ag+ (ag) + Cl - (aq) → AgCI(s)       Δ H = - 65.5 ...

Solved • May 30, 2018

Thermochemical Equation

Q. If the heat of combustion for a specific compound is -1090.0 kJ/mol and its molar mass is 48.47 g/mol, how many grams of this compound must you bur...

Solved • May 21, 2018

Thermochemical Equation

Q. How much heat in kilojoules is evolved or absorbed in each of the following reactions?Burning of 15.5 g of propane:C3H8(g) + 5 O2(g) → 3 CO2(g) + C...

Solved • May 21, 2018

Thermochemical Equation

Q. A gas mixture at 580.0°C and 113 kPa absolute enters a heat exchanger at a rate of 80.0 m3/hr. The gas leaves the heat exchanger at 150.0°C. The ch...

Solved • May 12, 2018

Thermochemical Equation

Q. Consider the following thermochemical equation for the combustion of acetone (C3H4O), the main ingredient in nail polish remover. C3H6O(l) + 4 O2(g...

Solved • May 4, 2018

Thermochemical Equation

Q. The combustion of hexane is given by the following reaction. 2C6H14 + 19O2 --> 12CO2 + 14H2O The enthalpy of reaction is -4163.0 kJ/mol. How muc...

Solved • May 4, 2018

Thermochemical Equation

Q. Hydrazine, N2H4, is a liquid used as a rocket fuel. It reacts with oxygen to yield nitrogen gas and water.N2H4 (l) + O2 (g) → N2 (g) + 2 H2O (l)The...

Solved • May 4, 2018

Thermochemical Equation

Q. The reaction for the combustion of propane is shown below. C3H8(g) + 5 O2 (g) → 3 CO2 (g)  + 4 H2O (l)    ΔH = - 526.3 kcal/molHow much heat is  re...

Solved • Apr 3, 2018

Thermochemical Equation

Q. What is the minimum energy required to decompose 765 g of PCl 3, according to the reaction below? The molar mass of PCl3 is 137.32 g/mol. 4PCl3(g) ...

Solved • Apr 2, 2018

Thermochemical Equation

Q. The enthalpy of neutralization for the reaction of HNO3 with KOH is given below.HNO3 (aq) + KOH (aq) → H2O (l) + KNO3 (aq)    ΔH = -57.0 kJ102.4 ml...

Solved • Mar 21, 2018

Thermochemical Equation

Q. Calcium oxide and water react in an exothermic reaction:CaO(s) + H2O(l) → Ca(OH)2(s)       Heat of reaction (Rxn) = -64.8 kJ/molHow much heat would...

Solved • Mar 21, 2018

Thermochemical Equation

Q. What volume of benzene (C6H6, d= 0.88 g/mL, molar mass = 78.11 g/mol) is required to produce 1.5 x 103 kJ of heat according to the following reacti...

Solved • Mar 20, 2018

Thermochemical Equation

Q. In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water:CH4(g) + 2O2(g) → CO2(g) + 2H2O...

Solved • Mar 20, 2018

Thermochemical Equation

Q. How much heat is absorbed when 45.00 g of C(s) reacts in the presence of excess SO2(g) to produce CS2(l) and CO(g) according to the following chemi...

Solved • Mar 20, 2018

Thermochemical Equation

Q. Using the following thermochemical equation, determine the amount of heat produced from the combustion of 24.3 g benzene (C6H6). The molar mass of ...

Solved • Mar 20, 2018

Thermochemical Equation

Q. Using the following equation for the combustion of octane, calculate the heat associated with the combustion of excess octane with 100.0 g of oxyge...

Solved • Mar 20, 2018

Thermochemical Equation

Q. If the heat of combustion for a specific compound is -1180.0 kJ/mol and its molar mass is 94.65 g/mol how many grams of this compound must you burn...

Solved • Mar 13, 2018

Thermochemical Equation

Q. Potassium nitrate, KNO3, has a molar mass of 101.1 g/mol. In a constant-pressure calorimeter, 32.3 g of KNO3 is dissolved in 243 g of water at 23.0...

Solved • Dec 14, 2017

Thermochemical Equation

Q. The third step in converting SiO2  to Si is:SiCl4 (g) + 2Mg(s) → 2MgCl2 (s) + Si(s) ΔH = -625.6 kJ. What is the enthalpy change when 4.248 kg of si...

Solved • Oct 13, 2017

Thermochemical Equation

Q. Given the thermochemical equation 2SO2(g) + O(g) → 2SO3(g), ΔH°rxn = -198 kJ, how much heat is evolved when 600.g of SO2 is burned? a) 5.46 x 10-2...

Solved • Aug 24, 2017

Thermochemical Equation

Q. Determine the amount of heat (in kJ) given off when 1.26 x 10 4 g of NO2 are produced according to the equation: 2NO(g) + O2(g) → 2NO2(g)         ...

Solved • Jul 17, 2017

Thermochemical Equation

Q. Calculate the amount of heat (kJ) released in the complete combustion of 8.17 g of Al to form aluminum oxide at 25°C and under a pressure of 1 atm....

Solved • Jul 3, 2017

Thermochemical Equation

Q. Hydrogen peroxide decomposes according to the following thermochemical reaction:                   H2O2   →   H2O   +   ½ O2                       ...

Solved • Jul 3, 2017

Thermochemical Equation

Q. An LP gas tank in a home barbeque contains 13.2 kg propane (C3H8). Calculate the heat (kJ) associated with the complete combustion of all the propa...

Solved • Jul 3, 2017

Thermochemical Equation

Q. Carbon monoxide reacts with oxygen to form carbon dioxide by the following reaction:2 CO(g) + O2(g) → 2 CO2(g)∆H for this reaction is −135.28 kcal....

Solved • Jun 21, 2017

Thermochemical Equation

Q. The heat of combustion of butane (C4H10) is −2878 kJ/mol. Assume a typical cigarette lighter holds about 1.75 g of butane. How much heat energy wou...

Solved • Jan 17, 2017

Thermochemical Equation

Q. When 5.50 g of Ba(s) is added to 100.00 g of water in a container open to the atmosphere, the reaction shown below occurs and the temperature of th...

Solved • Oct 26, 2016

Thermochemical Equation

Q. Calculate the mass of water that can be vaporized with 155 kJ of heat at 100 oC? (Molar Mass of Water= 18.02 g/mol) a. 12.5 gb. 36.0 gc. 68.6 gd. 8...

Solved • Sep 23, 2016

Thermochemical Equation

Q. When 1.0 mole of calcium hydroxide is neutralized by hydrochloric acid, ΔH = -111.7 kJ. If you reacted 63.3 mL of a 2.8 M HCl with 33.3 mL of 3.2 M...

Solved • Aug 24, 2016

Thermochemical Equation

Q. Consider the process of 2 H(g) → H2(g) where ΔH = −436 kJ/mol Determine if the sentence below is true or false. Reacting two moles of H(g) would ...

Solved • Aug 8, 2016

Thermochemical Equation

Q. Consider the following reaction:CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O(g) If 16.04 g of CH4  completely reacting in the above reaction gives out 802 ...

Solved • Aug 8, 2016

Thermochemical Equation

Q. Given the chemical reaction: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g)                 ΔH = −2044 kJ How much energy would be released if 2.0 moles...

Solved • Aug 8, 2016

Thermochemical Equation

Q. Methanol (CH3OH) is used as a fuel in race cars. (d) Calculate the mass of CO2 produced per kJ of heat emitted. 

Solved • Jul 14, 2016

Thermochemical Equation

Q. Methanol (CH3OH) is used as a fuel in race cars. (c) Calculate the heat produced by combustion per liter of methanol. Methanol has a density of 0.7...

Solved • Jul 14, 2016

Thermochemical Equation

Q. Methanol (CH3OH) is used as a fuel in race cars. (a) Write a balanced equation for the combustion of liquid methanol in air.

Solved • Jul 14, 2016

Thermochemical Equation

Q. Consider the decomposition of liquid benzene, C6H6 (l), to gaseous acetylene, C2H2 (g):C6H6 (l) → 3 C2H2 (g)         ΔH = +630 kJ(b) What is ΔH for...

Solved • Jul 13, 2016

Thermochemical Equation

Q. Consider the combustion of liquid methanol, CH 3OH (l):CH3OH (l) + 3/2 O2 (g) → CO2 (g) + 2 H2O (l)     ΔH = -726.5 kJ(b) Balance the forward react...

Solved • Jul 13, 2016

Thermochemical Equation

Q. Consider the following reaction: CH3OH (g) → CO (g) + 2 H 2 (g)       ΔH = +90.7 kJ(d) How many kilojoules of heat are released when 50.9 g of CO(g...

Solved • Jul 13, 2016

Thermochemical Equation

Q. Consider the following reaction: CH3OH (g) → CO (g) + 2 H 2 (g)       ΔH = +90.7 kJ(c) For a given sample of CH3OH, the enthalpy change on reaction...

Solved • Jul 13, 2016

Thermochemical Equation

Q. Consider the following reaction: CH3OH (g) → CO (g) + 2 H 2 (g)       ΔH = +90.7 kJ(b) Calculate the amount of heat transferred when 45.0 g of CH 3...

Solved • Jul 13, 2016

Thermochemical Equation

Q. What mass and volume of benzene (C6H6, d= 0.88 g/mL, molar mass = 78.11 g/mol) is required to produce 3.3 x 108 kJ of heat according to the followi...

Solved • May 26, 2016

Thermochemical Equation

Q. How much energy is required to vaporize 22.7 g of dichloromethane (CH 2Cl2) at its boiling point, if its ΔHvap is 31.6 kJ/mol? The molar mass of di...

Solved • Apr 6, 2016

Thermochemical Equation

Q. What mass of water would need to evaporate from your skin in order to dissipate 1.7 x 105 J of heat from your body? H2O(l) → H2O(g)           ΔH v...

Solved • Mar 24, 2016

Thermochemical Equation

Q. A large part of the driving force in a thermite reaction is based on the stability of aluminum oxide, as reflected in ΔH° of the following reaction...

Solved • Feb 29, 2016

Thermochemical Equation

Q. Assuming the heat released from the combustion of CH 4 can be used with 100% efficiency, how much CH4 (in g) is required to be combusted in the pre...

Solved • Feb 22, 2016

Thermochemical Equation

Q. 10.1 g CaO is dropped into a Styrofoam coffee cup containing 157 g H2O at 18.0ºC. If the following reaction occurs, what temperature will the water...

Solved • Feb 12, 2016

Thermochemical Equation

Q. Sucrose (table sugar, C12H22O11) can be oxidized to form what two products via a combustion mechanism? What is the enthalpy change when 5.00 g of s...

Solved • Feb 12, 2016

Thermochemical Equation

Q. What volume of benzene (C6H6, d= 0.88 g/mL, molar mass = 78.11 g/mol) is required to produce 1.5 x 103 kJ of heat according to the following reaction?

Solved • Feb 12, 2016

Thermochemical Equation

Q. A 21.8 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter, according to the following reaction. If the temperature rises from 25.0 to 62....

Solved • Feb 12, 2016

Thermochemical Equation

Q. Consider the following thermochemical reaction for the combustion of acetone, C3H6O, the main component of nail polish remover: 

Solved • Feb 12, 2016