Question 1

Which of the following best describes the purpose of a gas stoichiometric chart in chemical calculations?

Accepted Answer

To use the given quantity of a compound to determine the unknown quantity of another compound.

Question 2

In the reaction $$4Ag(s) + O_2$(g) \rightarrow 2Ag_2O(s)$$, what is the mole ratio of silver to silver oxide?

Accepted Answer

$$4:2$$

Question 3

A student is given 384 mL of $$O_2$$ gas at 736 mmHg and 25°C to react with excess $$Ag. $$Using the reaction $$4Ag(s) + O_2$(g) \rightarrow 2Ag_2O(s)$$, what is the first step in determining the mass of $$Ag_2O$$ produced?

Accepted Answer

Convert the volume of $$O_2 to $$moles using the ideal gas law.

Question 4

Given the reaction $$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O$$, how many moles of $$CO_2$$ are produced when 1 mole of glucose is completely metabolized?

Accepted Answer

6 moles

Question 5

If 1728.7 grams of glucose ($$C_6H_{12}O_6$) are metabolized, how many moles of glucose are used? (Molar mass = 180.156 g/mol)

Accepted Answer

$$9.59$$ moles

Question 6

In the reaction $$P_4(s) + 5O_2(g$$) \rightarrow 2P_2O_5(g)$$, what is the coefficient for O_2$ and what does it represent?

Accepted Answer

5; the number of moles of $$O_2$$ required per mole of $$P_4$$

Question 7

A reaction uses 1.85 L of $$P_2O_5$$ gas at 50°C and 1.12 atm. What is the correct sequence of steps to find the mass of $$P_4$$ that reacted?

Accepted Answer

Convert volume of $$P_2O_5 to $$moles, use mole ratio to find moles of $$P_4$$, convert moles of $$P_4 to $$grams.

Question 8

Which equation is used to convert the volume of a gas to moles under non-standard conditions?

Accepted Answer

$$PV = nRT$$

Question 9

In the reaction $$4NH_3(g) + 5O_2(g) \rightarrow 4NO(g) + 6H_2O(g)$$, how many moles of water are produced when 4 moles of ammonia react completely?

Accepted Answer

6 moles

Question 10

A medical laboratory combusts 15.3 L of $$NH_3 (at 298 K $$and 1.50 atm) with 21.7 L of $$O_2 (at 323 K $$and 1.41 atm). Which reactant is the limiting reagent?

Accepted Answer

$$NH_3$$

Question 11

Which step in a stoichiometry problem involves using the coefficients from the balanced equation?

Accepted Answer

Mole to mole comparison

Question 12

A student calculates the volume of $$CO_2$$ produced at 34°C and 1.00 atm from the metabolism of 231.88 g of glucose. Which formula should be used to find the volume?

Accepted Answer

$$PV = nRT$$

Question 13

If 6 moles of $$O_2$$ are required to metabolize 1 mole of glucose, how many moles of $$O_2$$ are needed to metabolize 10 moles of glucose?

Accepted Answer

60 moles

Question 14

Which of the following is NOT a necessary step in solving a gas stoichiometry problem?

Accepted Answer

Balance the equation using only atomic numbers.

Question 15

A reaction produces 103.6 g of phosphorus from the oxidation of $$P_4$$ with $$O_2. $$What is the molar mass of $$P_4$$ used in the calculation?

Accepted Answer

$$124 g/$$mol

Question 16

Which real-world scenario best illustrates the application of gas stoichiometry?

Accepted Answer

Calculating the amount of oxygen needed for a patient’s ventilator.

Question 17

In the reaction $$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O$$, what is the total number of moles of products formed from 2 moles of glucose?

Accepted Answer

24 moles

Question 18

A student needs to convert grams of $$Ag_2O to $$moles. Which equation should they use?

Accepted Answer

$$n = \frac{m}{M}$$

Question 19

Why is it important to use the coefficients from a balanced chemical equation in stoichiometry?

Accepted Answer

They provide the mole ratios needed for conversions between substances.

Question 20

A hospital uses 500 g of $$C_6H_{12}O_6$ in a metabolic reaction. How many liters of CO_2$ are produced at 34°C and 1.00 atm? (Molar mass of glucose = 180.156 g/mol, R = 0.0821$ L·atm/mol·K)

Accepted Answer

$$PV = nRT$$; $$n = \frac{500}{180.156}$$; $$n_{CO_2$} = n_{glucose} 	imes 6$$; $$V = \frac{nRT}{P}$$

Stoichiometry and Gas Stoichiometry in Chemical Reactions

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