Question 1

Which of the following is the correct balanced chemical equation for the reaction between solid iron(III) oxide and hydrogen gas to form solid iron and liquid water?

Accepted Answer

$$\mathrm{Fe_2O_3(s) + 3H_2(g) \rightarrow 2Fe(s) + 3H_2O(l)}$$

Question 2

How many grams of water are produced when 7.5 g of HNO3 react with excess NaOH according to the equation: $$\mathrm{$$HNO_3$$(aq) + NaOH(aq) \rightarrow $$NaNO_3$$(aq) + H_2O(l)}$$? (Molar masses: HNO3 = 63.0 g/mol, H2O = 18.0 g/mol)

Accepted Answer

$$2.1\ \mathrm{g}$$

Question 3

How many moles of NH3 form when 2.81 kg of NH4Cl completely reacts according to the equation: $$\mathrm{NH_4Cl(s) + NaOH(aq) \rightarrow NH_3$(g) + NaCl(aq) + H_2O(l)}$$? (Molar mass NH4Cl = 53.5 g/mol)

Accepted Answer

$$52.5\ \mathrm{mol}$$

Question 4

A mixture initially contains 0.473 mol of HCl and 0.242 mol of Na2S. What is the limiting reactant according to the equation: $$\mathrm{2HCl(aq) + Na_2S(aq) \rightarrow 2NaCl(aq) + H_2S(g)}$$?

Accepted Answer

HCl

Question 5

Determine the molarity of a solution formed by dissolving 2.75 mol of KCl in 3.24 L of solution.

Accepted Answer

$$0.849\ \mathrm{M}$$

Question 6

A laboratory procedure calls for making 250.0 mL of a 1.3 M KNO3 solution. What mass of KNO3 is required? (Molar mass KNO3 = 101.1 g/mol)

Accepted Answer

$$32.9\ \mathrm{g}$$

Question 7

If 21.4 mL of 4.4 M MgCl2 solution is diluted to 32 L, what is the molarity of the diluted solution?

Accepted Answer

$$0.0029\ \mathrm{M}$$

Question 8

According to the reaction $$\mathrm{2HCl(aq) + Pb(NO_3$)_2(aq) \rightarrow $$PbCl_2$$(s) + 2HNO_3(aq)}$$, what mass of PbCl2 can form from 235 mL of 0.110 M HCl? (Molar mass PbCl2 = 278.1 g/mol)

Accepted Answer

$$3.55\ \mathrm{g}$$

Question 9

What volume of 0.305 M AgNO3 is required to react exactly with 155.0 mL of 0.274 M Na2CO3 solution? Use the balanced equation: $$\mathrm{2AgNO_3(aq) + Na_2CO_3(aq) \rightarrow Ag_2CO_3(s) + 2NaNO_3(aq)}.$$

Accepted Answer

$$278\ \mathrm{mL}$$

Question 10

Which compound is a strong electrolyte?

Accepted Answer

NaCl

Question 11

Give the net ionic equation for the reaction that occurs when aqueous solutions of H2SO4 and KOH are mixed.

Accepted Answer

$$\mathrm{2OH^-(aq) + 2H^+(aq) \rightarrow 2H_2O(l)}$$

Question 12

Select the correct net ionic equation for the reaction of aqueous H2SO4 with Ba(OH)2.

Accepted Answer

$$\mathrm{Ba$$^{2+}$$(aq) + SO_4$^{2-}(aq) \rightarrow $$BaSO_4$$(s)}$$

Question 13

Which of the following is NOT a strong electrolyte?

Accepted Answer

HC2H3O2

Question 14

Which of the following compounds are soluble in water?

Accepted Answer

LiNO3, NaCl

Question 15

A system releases 742 J of heat and does 343 J of work on the surroundings. What is the change in internal energy of the system?

Accepted Answer

$$\Delta E = -1085\ \mathrm{J}$$

Question 16

Determine the final temperature of a gold nugget (mass = 376 g) that starts at 298.0 K and absorbs 4.85 kJ of heat in a snowbank when it is hot. The specific heat capacity of gold is $$0.128\ \mathrm{J\ g$$^{-1}$$\ K$$^{-1}$$}.$$

Accepted Answer

$$308\ \mathrm{K}$$

Question 17

Use the bond energies provided to estimate $$\Delta H_{rxn}$$ for the reaction: $$\mathrm{CH_3OH(g) + O_2$(g) \rightarrow CO_2$(g) + 2H_2O(g)}.
$$Bond energies (kJ/mol): C-H: 414, C-O: 360, C=O: 799, O-H: 464, O=O: 498

Accepted Answer

$$-454\ \mathrm{kJ}$$

Question 18

Using the following equation for the combustion of octane, calculate the heat associated with the formation of 100.0 g of carbon dioxide. Molar mass of CO2 = 44.0 g/mol. $$\mathrm{2C_8H_{18}(l) + 25O_2(g) \rightarrow 16CO_2(g) + 18H_2O(g)}$$, $$\Delta H_{rxn} = -11018\ \mathrm{kJ}$$

Accepted Answer

$$-156\ \mathrm{kJ}$$

General Chemistry: Practice Problems on Chemical Quantities, Reactions, and Thermochemistry

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