Q: How many molecules of carbon dioxide are produced when $$0.75\ \mathrm{mol} of $$propane ($$\mathrm{C_3H_8}) is $$combusted according to the equation $$\mathrm{C_3H_8} + 5\mathrm{O_2$} \rightarrow 3\mathrm{CO_2$} + 4\mathrm{H_2O}$$?

$$1.4 \times 10$$^{24}$$ molecules

Question 1

A student wants to prepare a solution by dissolving 75.6 g of acetic acid ($$\mathrm{CH_3COOH}$$, molar mass = $$60.05\ \mathrm{g\ $$mol^{-1}$$}) in $$water. If the final concentration of the solution is $$0.839\ \mathrm{mol\ L$$^{-1}$$}$$, what is the volume of the solution in liters?

Accepted Answer

$$1.50\ \mathrm{L}$$

Question 2

How many milliliters of a $$2.53\ \mathrm{M}$$ glucose ($$\mathrm{C_6H_{12}O_6$}$$, molar mass = $$180.2\ \mathrm{g\ $$mol^{-1}$$}) $$solution are needed to obtain $$3.81\ \mathrm{g} of $$glucose?

Accepted Answer

$$8.36\ \mathrm{mL}$$

Question 3

What is the molarity of an ethanol ($$\mathrm{CH_3CH_2OH}) $$solution if $$1.77\ \mathrm{g} of $$ethanol is dissolved to make $$85.0\ \mathrm{mL} of $$solution? (Molar mass of ethanol = $$46.07\ \mathrm{g\ $$mol^{-1}$$})$$

Accepted Answer

$$0.0384\ \mathrm{M}$$

Question 4

A $$0.315\ \mathrm{M}$$ NaOH solution contains $$6.22\ \mathrm{g} of $$NaOH. What is the volume of the solution in liters? (Molar mass of NaOH = $$40.0\ \mathrm{g\ $$mol^{-1}$$})$$

Accepted Answer

$$0.4936\ \mathrm{L}$$

Question 5

What is the concentration of ammonium ions in a $$0.0236\ \mathrm{M}$$ ammonium sulfate ($$\mathrm{(NH_4$)_2SO_4}) $$solution?

Accepted Answer

$$0.0472\ \mathrm{M}$$

Question 6

A solution is made by dissolving $$45.0\ \mathrm{g} of $$glycerol ($$\mathrm{C_3H_8O_3}$$, molar mass = $$92.094\ \mathrm{g\ $$mol^{-1}$$}) in$$ $$50.0\ \mathrm{g} of $$water. The density of the solution is $$1.095\ \mathrm{g\ mL$$^{-1}$$}. $$What is the molarity of the solution?

Accepted Answer

$$0.4886\ \mathrm{M}$$

Question 7

Which of the following best describes the difference between formula stoichiometry and reaction stoichiometry?

Accepted Answer

Formula stoichiometry uses the actual chemical formulas, while reaction stoichiometry uses the coefficients from the balanced equation.

Question 8

How many molecules of carbon dioxide are produced when $$0.75\ \mathrm{mol} of $$propane ($$\mathrm{C_3H_8}) is $$combusted according to the equation $$\mathrm{C_3H_8} + 5\mathrm{O_2$} \rightarrow 3\mathrm{CO_2$} + 4\mathrm{H_2O}$$?

Accepted Answer

$$1.4 	imes 10$$^{24}$$ molecules

Question 9

Methanol burns in air according to the equation $$2\mathrm{CH_3OH} + 3\mathrm{O_2$} \rightarrow 2\mathrm{CO_2$} + 4\mathrm{H_2O}. If$$ $$3.0\ \mathrm{g} of $$methanol are combusted, what mass of water is produced? (Molar mass of methanol = $$32.0\ \mathrm{g\ $$mol^{-1}$$}$$, water = $$18.0\ \mathrm{g\ $$mol^{-1}$$})$$

Accepted Answer

$$3.38\ \mathrm{g}$$

Question 10

Potassium chlorate ($$\mathrm{$$KClO_3$$}) $$decomposes according to $$2\mathrm{$$KClO_3$$}(s) \rightarrow 2\mathrm{KCl}(s) + 3\mathrm{O_2$}(g). $$How many grams of $$\mathrm{O_2$}$$ can be prepared from $$4.50\ \mathrm{g} of$$ $$\mathrm{$$KClO_3$$}$$? (Molar mass $$\mathrm{$$KClO_3$$}$$ = $$122.55\ \mathrm{g\ $$mol^{-1}$$}$$, $$\mathrm{O_2$}$$ = $$31.9988\ \mathrm{g\ $$mol^{-1}$$})$$

Accepted Answer

$$1.77\ \mathrm{g}$$

Question 11

In a reaction, $$200.0\ \mathrm{g} of $$silicon and $$150.0\ \mathrm{g} of $$nitrogen react to form silicon nitride ($$\mathrm{Si_3N_4}) $$according to $$3\mathrm{Si} + 2\mathrm{N_2$} \rightarrow \mathrm{Si_3N_4}. $$Which reactant is limiting?

Accepted Answer

Silicon

Question 12

Zinc reacts with silver nitrate according to $$\mathrm{Zn}(s) + 2\mathrm{$$AgNO_3$$}(aq) \rightarrow 2\mathrm{Ag}(s) + \mathrm{Zn(NO_3$)_2}(aq). If$$ $$2.00\ \mathrm{g} of Zn $$and $$2.50\ \mathrm{g} of $$AgNO$$_3$$ are used, which reactant is limiting? (Molar mass Zn = $$65.38\ \mathrm{g\ $$mol^{-1}$$}$$, AgNO$$_3$$ = $$169.87\ \mathrm{g\ $$mol^{-1}$$})$$

Accepted Answer

Silver nitrate

Question 13

In the reaction $$\mathrm{Zn}(s) + 2\mathrm{$$AgNO_3$$}(aq) \rightarrow 2\mathrm{Ag}(s) + \mathrm{Zn(NO_3$)_2}(aq)$$, if $$2.50\ \mathrm{g} of $$AgNO$$_3 is $$the limiting reactant, how many grams of Ag will form? (Molar mass Ag = $$107.87\ \mathrm{g\ $$mol^{-1}$$})$$

Accepted Answer

$$1.59\ \mathrm{g}$$

Question 14

In the same reaction, how many grams of $$\mathrm{Zn(NO_3$)_2}$$ will form from $$2.50\ \mathrm{g} of $$AgNO$$_3$$? (Molar mass $$\mathrm{Zn(NO_3$)_2}$$ = $$189.4\ \mathrm{g\ $$mol^{-1}$$})$$

Accepted Answer

$$1.39\ \mathrm{g}$$

Question 15

After the reaction between $$2.00\ \mathrm{g} Zn $$and $$2.50\ \mathrm{g}$$ AgNO$$_3 is $$complete, how many grams of excess Zn remain? (Molar mass Zn = $$65.38\ \mathrm{g\ $$mol^{-1}$$})$$

Accepted Answer

$$1.52\ \mathrm{g}$$

Question 16

In the reduction of iron(II,III) oxide with carbon monoxide, $$\mathrm{Fe_3O_4}(s) + 3\mathrm{CO}(g) \rightarrow 2\mathrm{Fe}(s) + 3\mathrm{CO_2$}(g)$$, if $$245.0\ \mathrm{g} of$$ $$\mathrm{Fe_3O_4}$$ and $$120.2\ \mathrm{g} of CO $$are used, what is the theoretical yield of Fe? (Molar mass $$\mathrm{Fe_3O_4}$$ = $$159.69\ \mathrm{g\ $$mol^{-1}$$}$$, CO = $$28.01\ \mathrm{g\ $$mol^{-1}$$}$$, Fe = $$55.85\ \mathrm{g\ $$mol^{-1}$$})$$

Accepted Answer

$$159.8\ \mathrm{g}$$

Question 17

If the actual yield of Fe in the above reaction is $$87.9\ \mathrm{g}$$, what is the percent yield?

Accepted Answer

$$55.0\%$$

Solutions, Molarity, and Stoichiometry in General Chemistry

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