11650 Chemistry Practice Problems

Acetone is a common solvent and has a density of 0.7899 g/mL. What volume of acetone, in mL has a mass of 4.15 g? 

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Translate the following numbers into standard notation, maintaining the same number of significant figures. 

a. 4.52 x 103 

b.  8.11 x 10-2 

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Consider this system at equilibrium. 

PCl3(g) + Cl2(g) ⇌ PCI5(g) + heat 

How will the system respond to a temperature increase? 

a. shift left

b. shift right

c. no change

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Write the equilibrium-constant expression for the reaction

2 NO(g) + O2(g) ⇌ 2 NO2(g)

in terms of [NO], [O2], and [NO2].

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Assuming equal concentrations, rank these solutions by pH. 

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A monoprotic acid, HA, is dissolved in water: 

HA ⇌ H+ + A- 

The equilibrium concentrations of the reactants and products are 

[HA] = 0.240 M 

[H+] = 2.00 x 10-4

[A-] = 2.00 x 10-4

Calculate the value of pKa for the acid HA.

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A student measures 49.9 mL of concentrated nitric acid, which has a density of 1.50 g/mL. 

What is the mass of the acid? Express your answer in grams to three significant figures.

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Write the chemical symbols for three different atoms or atomic cations with 26 electrons.

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A carbon-hydrogen bond in ethane (CH3CH3) is best described as 

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In the compound sodium methoxide (NaOCH3), there is ___ bonding

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Question 3

What is the pH of a 0.500M strontium hydroxide solution?

Question 4

Calculate the pH of a 0.250M formic acid (HCOOH) solution. Ka for formic acid is 1.8 x 10-4.

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Question 2

Calculate the pH of a solution with [OH-] equal to 2.9 x 10-4 M. 

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[OH-] = 5.5 x 10-9

Express the molarity to two significant figures. 

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Given that 8.33 moles of carbon monoxide gas are present in a container of volume 26.10 L, what is the pressure of the gas (in atm) if the temperature is 47°C?

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A glucose solution contains 58.5 g of glucose (C6H12O6) in 460 g of water. 

Part A

Compute the freezing point and boiling point of the solution. (Assume a density water.)

Part B 

Compute the freezing point and boiling point of the solution. (Assume a density water.) 

Express your answer using six significant figures. 

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Given the following acids and Ka values: 

HClO4                  HOAc                     HCN                    HF 

1 x 107                 1.76 x 10-5             4.93 x 10-10         3.53 x 10-4 

What is the order of increasing base strength?

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What is the volume of 5.37 moles of an ideal gas at 35.5°C and 1.00 atm?

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Consider the reaction: 

2NiO (s) → 2Ni (s)+ O2 (g) 

Oxygen gas is collected over water at 40.0°C and a barometric pressure of 745 torr. What volume of oxygen will be collected for the complete reaction of 24.8 g NiO? 

You must show the key steps in the calculation to get the full credit even for the correct answer.

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Give the SYSTEMATIC name for each of the following compounds: 

(a) Hg2(OH)2

(b) CrO3 [Cr = Chromium] 

(c) H2SO3 (aq) 

(d) HClO3 (aq) 

(e) Fe3N2

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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 2

What is the concentration of N2Oat equilibrium?

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How many grams of carbon disulfide are needed to completely consume 53.3 L of chlorine gas according to the following reaction at 25°C and 1 atm? 

carbon disulfide (s) + chlorine (g) → carbon tetrachloride (l) + sulfur dichloride (s) 

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0.976 mol sample of helium gas at a temperature of 24.0°C is found to occupy a volume of 21.2 liters. The pressure of this gas sample is ___ mm Hg.

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A sample of argon gas collected at a pressure of 626 mm Hg and a temperature of 287 K has a mass of 28.1 grams. The volume of the sample is ____ L.

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A sample of helium gas collected at a pressure of 0.976 atm and a temperature of 24.0°C is found to occupy a volume of 21.2 liters. How many moles of He gas are in the sample?

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A sample of argon gas collected at a pressure of 0.702 atm and a temperature of 291 K is found to occupy a volume of 653 millimeters. How many moles of Ar gas are in the sample?

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