48 Stoichiometry Practice Problems for DAT Exam Prep

IV. Stoichiometry and Solution questions

Stoichiometry practice problems

These 48 practice questions cover the key stoichiometry and solution concepts in this chapter’s summary. Aim to spend about 1 minute per question. After each test, select “See Result” to review your answers. Incorrect answers are marked in red, and correct answers are marked in green. An explanation appears below each question.

STOICHIOMETRY AND SOLUTION TEST 1

1 / 20

A sample of an unknown compound has a mass of 32 g and fills a cube with an edge length of 2 cm. What is its density?

A. 32 g/cm³

B. 16 g/cm³

C. 8 g/cm³

D. 4 g/cm³

E. 2 g/cm³

Solution:

2 / 20

Each listed container holds exactly 1.00 mol of the named substance. Which has the greatest mass of substance per liter of container volume? Use these rounded molar masses: H₂, 2 g/mol; F₂, 38 g/mol; Cl₂, 71 g/mol; Br₂, 160 g/mol; I₂, 254 g/mol.

A. H₂ in 2L container

B. F₂ in 20L container

C. Cl₂ in 40L container

D. Br₂ in 40L container

E. I₂ in 160L container

Solution:

3 / 20

What is the mass percent of carbon in C₃H₆O₃?

A. 15%

B. 20%

C. 40%

D. 50%

E. 60%

Solution:

Corrected calculation for question 503

4 / 20

What is the mass percent of hydrogen in water?

A. 11.1%

B. 88.9%

C. 12.5%

D. 25.0%

E. 9.0%

Solution:

Corrected calculation for question 504

5 / 20

Approximately what is the mass percent of oxygen in Cu(NO₃)₂?

A. 9%

B. 26%

C. 43%

D. 51%

E. 65%

Solution:

Corrected calculation for question 505

6 / 20

A 110.0 g sample contains only silver and chlorine. If 40.0 g of the sample is chlorine, what is the mass percent of silver?

A. 36.4%

B. 63.6%

C. 107.9%

D. 98.1%

E. 67.8%

Solution:

7 / 20

A solution is prepared using 50 g of SO₂ and water. If the mass percent of SO₂ is 25%, how many grams of water are needed?

A. 12.5 g

B. 50.0 g

C. 100.0 g

D. 150.0 g

E. 200.0 g

Solution:

8 / 20

How many moles of calcium atoms and oxygen atoms, respectively, are present in 50 g of CaCO₃?

A. 0.5 mol of calcium atoms, 1.5 mol of oxygen atoms

B. 0.5 mol of calcium atoms, 0.5 mol of oxygen atoms

C. 1.5 mol of calcium atoms, 1.5 mol of oxygen atoms

D. 1.2 mol of calcium atoms, 1.0 mol of oxygen atoms

E. 1.2 mol of calcium atoms, 3.6 mol of oxygen atoms

Solution:

Corrected calculation for question 508

9 / 20

Approximately how many carbon atoms are present in 120 g of saccharin, C₇H₅NO₃S?

A. 2.8 × 10²⁴

B. 4.0 × 10²³

C. 6.0 × 10²³

D. 2.0 × 10²³

E. 1.2 × 10²⁴

Solution:

Corrected calculation for question 509

10 / 20

What is the mass of 2 mol of glucose, C₆H₁₂O₆?

A. 90 g

B. 180 g

C. 360 g

D. 400 g

E. 460 g

Explanation:

The molar mass of glucose is approximately (6 × 12) + (12 × 1) + (6 × 16) = 180 g/mol. Thus, 2 mol × 180 g/mol = 360 g.

11 / 20

A sample contains 2.1 × 10²⁴ formula units of ZnCl₂. What is its mass to two significant figures? Use a molar mass of 136.28 g/mol and N_A = 6.022 × 10²³ mol⁻¹.

A. 39 g

B. 135 g

C. 270 g

D. 4.8 × 10² g

E. 2.8 × 10²⁶ g

Solution:

12 / 20

A sample contains 1.2 × 10²³ formula units of sodium oxide, Na₂O. Which statement is INCORRECT? Use N_A = 6.0 × 10²³ mol⁻¹, Na = 23 g/mol, and O = 16 g/mol.

A. The mass of Na₂O is 12.4 g.

B. The sample contains 2.4 × 10²³ Na⁺ ions.

C. The sample contains 0.20 mol of ions in total.

D. The mass of O is 3.2 g.

E. The number of Na₂O formula units equals the number of O²⁻ ions.

Solution:

Corrected calculation for question 512

13 / 20

Palladium is used in dental porcelain-fused-to-metal crowns. Approximately how many atoms are in 212 g of Pd? Use a molar mass of 106 g/mol and N_A = 6.0 × 10²³ mol⁻¹.

A. 3.0 × 10²³

B. 6.0 × 10²³

C. 1.2 × 10²⁴

D. 6.4 × 10²⁴

E. 1.2 × 10²⁵

Solution:

Corrected calculation for question 513

14 / 20

How many grams of nitrogen are present in 16 g of N₂H₄?

A. 14 g

B. 28 g

C. 42 g

D. 56 g

E. 64 g

Solution:

Corrected calculation for question 514

15 / 20

A compound contains 224 g of iron and 96 g of oxygen. What is its empirical formula?

A. FeO₃

B. Fe₂O₆

C. Fe₂O₃

D. Fe₄O₆

E. Fe₃O

Solution:

Corrected calculation for question 515

16 / 20

An unknown compound contains 43.4% Na, 11.3% C, and 45.3% O by mass. What is its empirical formula?

A. Na₂CO₃

B. Na₄CO₆

C. NaC₂O₃

D. Na₈C₂O₁₂

E. Na₂CO₆

Solution:

Corrected calculation for question 516

17 / 20

Caproic acid has the empirical formula C₃H₆O and a molar mass of 116 g/mol. What is its molecular formula?

A. C₁H₂O_0.5

B. C₃H₆O

C. C₆H₁₂O₂

D. C₉H₁₈O₃

E. C₁₂H₂₄O₄

Explanation:

The empirical formula mass corresponds to a molar mass of (3 × 12) + 6 + 16 = 58 g/mol. The multiplier is 116/58 = 2. Multiplying each subscript by 2 gives C₆H₁₂O₂.

18 / 20

An unknown compound has a molar mass of 58 g/mol. Which could be its empirical formula?

A. C₄H₁₀

B. C₂H₅

C. C₂H₆

D. CH₃

E. C₂H₃

Solution:

Corrected calculation for question 518

19 / 20

Carbon reacts with Fe₂O₃ as shown. After balancing with the smallest whole-number coefficients, what is the sum of the product coefficients?

Fe₂O₃ + C → Fe + CO₂

A. 2

B. 3

C. 5

D. 7

E. 9

Solution:

20 / 20

Butane undergoes complete combustion in O₂ to form CO₂ and H₂O. What is the sum of all coefficients in the balanced equation, using the smallest whole-number coefficients?

A. 4

B. 15

C. 18

D. 25

E. 33

Solution:

Your score is

The average score is 44%

STOICHIOMETRY AND SOLUTION TEST 2

1 / 20

A 180 g sample of C₃H₈O reacts with excess O₂ and produces 277.2 g of CO₂. What is the percent yield of CO₂?
2C₃H₈O + 9O₂ → 6CO₂ + 8H₂O

A. 70%

B. 75%

C. 80%

D. 85%

E. 90%

Solution:

Corrected calculation for question 521

2 / 20

If 67.2 g of Fe reacts with 32.0 g of O₂, what is the theoretical yield of Fe₂O₃? Use Fe = 56.0 g/mol and O = 16.0 g/mol.

4Fe + 3O₂ → 2Fe₂O₃

A. 43 g

B. 52 g

C. 80 g

D. 96.0 g

E. 172 g

Solution:

Corrected calculation for question 522

3 / 20

How many grams of PH₃ must react to produce 54 g of H₂O? Assume excess O₂ and complete reaction.
4PH₃ + 8 O₂ → P₄O₁₀ + 6H₂O

A. 17 g

B. 34 g

C. 51 g

D. 60 g

E. 68 g

Solution:

Corrected calculation for question 523

4 / 20

Approximately how many grams of Cl₂ are required to react with 2.8 × 10² g of Si? Use Si = 28.0 g/mol and Cl = 35.5 g/mol.

Si + 2Cl₂ → SiCl₄

A. 350 g

B. 700 g

C. 1.4 × 10³ g

D. 2800 g

E. 3500 g

Solution:

5 / 20

How many grams of MgCl₂ must be dissolved in 9 g of water to prepare a solution that is 40% MgCl₂ by mass?

A. 3 g

B. 6 g

C. 9 g

D. 12 g

E. 15 g

Solution:

6 / 20

A KCl solution is prepared by dissolving 148 g of KCl in water and adjusting the final solution volume to 400 mL. Approximately what is its molarity? Assume all KCl dissolves.

A. 5 M

B. 10 M

C. 20 M

D. 185 M

E. 370 M

Solution:

Corrected calculation for question 526

7 / 20

How many grams of aspirin, C₉H₈O₄, are needed to prepare 250 mL of a 1.0 M solution in dichloromethane, CH₂Cl₂? The final solution volume is 250 mL.

A. 0.25 g

B. 25 g

C. 45 g

D. 90 g

E. 180 g

Solution:

Corrected calculation for question 527

8 / 20

Water is added to 300 mL of 12 M NaOH to obtain a 4 M solution. How much water is added? Assume volumes are additive.

A. 300 mL

B. 600 mL

C. 900 mL

D. 1200 mL

E. 1500 mL

Solution:

Corrected calculation for question 528

9 / 20

In a 0.25 M H₃PO₄ solution, how many moles of oxygen atoms contributed by H₃PO₄ are present per liter of solution? Exclude oxygen in the water.

A. 0.25 M

B. 0.5 M

C. 0.75 M

D. 1.0 M

E. 4.0 M

Explanation:

Each mole of H₃PO₄ contains 4 mol of oxygen atoms. Therefore, 0.25 mol H₃PO₄/L × 4 mol O atoms/mol H₃PO₄ = 1.0 mol O atoms/L. Oxygen in the water is excluded.

10 / 20

A solution contains 18 g of acetic acid, CH₃COOH, dissolved in 200 g of water. What is its molality?

A. 0.3 m

B. 1.5 m

C. 3.0 m

D. 4.5 m

E. 5.0 m

Solution:

Corrected calculation for question 530

11 / 20

A solution is prepared by dissolving 400 g of an unknown compound in 5 kg of water. Its molality is 4 m. Which compound matches the calculated molar mass?

A. HF

B. NaOH

C. Ca(OH)₂

D. H₂SO₄

E. HI

Solution:

Corrected calculation for question 531

12 / 20

Using the given data, a 5.00 M NaCl solution has a density of 1.09 g/mL. What is its molality? Use a molar mass of 58.0 g/mol for this calculation.

A. 3.50 m

B. 6.25 m

C. 10.40 m

D. 11.25 m

E. 15.50 m

Solution:

Corrected calculation for question 532

13 / 20

What volume of 0.850 M KOH(aq) is needed to neutralize 60.0 mL of 0.350 M HBr?

A. 145.7 mL

B. 72.8 mL

C. 49.4 mL

D. 24.7 mL

E. 12.4 mL

Solution:

14 / 20

What is the final molarity when 30.0 mL of water is added to 50.0 mL of 12.5 M KOH? Assume volumes are additive and report the answer to two significant figures.

A. 7.8 M

B. 15.6 M

C. 20.8 M

D. 31.2 M

E. 41.6 M

Solution:

15 / 20

An 80.0 mL sample of 4.0 M BaCl₂ is concentrated to a final volume of 50.0 mL by removing solvent. What formal concentration is calculated? Assume no solute is lost and ignore precipitation.

A. 1.3 M

B. 2.5 M

C. 5.0 M

D. 6.4 M

E. 12.8 M

Solution:

16 / 20

Approximately what volume of 2.0 M boric acid, B(OH)₃, is needed to react with 750 mL of 5.0 M NaOH according to the aqueous reaction below? Report the answer to two significant figures.

B(OH)₃ + OH⁻ → B(OH)₄⁻

A. 312 mL

B. 625 mL

C. 938 mL

D. 1250 mL

E. 1.9 × 10³ mL

Solution:

17 / 20

A 5.00 L aqueous suspension of Mg(OH)₂ completely neutralizes 100.0 L of 0.0150 M HCl. What is the analytical concentration of Mg(OH)₂, expressed as moles per liter of suspension?

Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

A. 0.00100 mol/L

B. 0.0750 mol/L

C. 0.150 mol/L

D. 0.300 mol/L

E. 0.600 mol/L

18 / 20

What are the products of the following reaction?

Pb(NO₃)₂(aq) + Na₂SO₄(aq) →

A. PbNa₂(aq) + (NO₃)₂SO₄(aq)

B. PbSO₄(s) + 2NaNO₃(aq)

C. PbNa₂(aq) + 2NaNO₃(aq)

D. PbSO₄(s) + (NO₃)₂SO₄(aq)

E. Pb(NO₂)₂(aq) + Na₂SO₃(aq) + O₂(g)

Explanation:

The balanced molecular equation is Pb(NO₃)₂(aq) + Na₂SO₄(aq) → PbSO₄(s) + 2NaNO₃(aq). The net ionic equation is Pb²⁺(aq) + SO₄²⁻(aq) → PbSO₄(s). Na⁺ and NO₃⁻ are spectator ions.

19 / 20

Which of the following is a redox reaction?

A. 2AgNO₃(aq) + Cu(s) → Cu(NO₃)₂(aq) + 2Ag(s)

B. 3MgCl₂(aq) + 2K₃PO₄(aq) → Mg₃(PO₄)₂(s) + 6KCl(aq)

C. LiOH(aq) + HI(aq) → LiI(aq) + H₂O(l)

D. AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq)

E. HF(aq) + KOH(aq) → H₂O(l) + KF(aq)

Solution:

Corrected calculation for question 539

20 / 20

Which substance is least soluble in water at room temperature?

A. AgCl

B. H₂SO₄

C. NaI

D. CaCl₂

E. NaOH

Explanation:

AgCl is sparingly soluble in water. Chlorides, bromides, and iodides of Ag⁺, Hg₂²⁺, and Pb²⁺ are common exceptions to the usual halide-solubility rule. The mercury(I) ion is Hg₂²⁺, not Hg₂⁺. Lead halide solubility depends appreciably on temperature.

Your score is

The average score is 48%

STOICHIOMETRY AND SOLUTION TEST 3

1 / 8

Which substance is a nonelectrolyte in water?

A. CH₃COOH

B. KOH

C. C₁₂H₂₂O₁₁

D. HNO₃

E. KBr

Explanation:

Sucrose, C₁₂H₂₂O₁₁, dissolves as neutral molecules and is a nonelectrolyte. Acetic acid is a weak electrolyte. KOH, HNO₃, and KBr are strong electrolytes in water. Organic compounds are not universally nonelectrolytes.

2 / 8

Which of the following is a strong acid?

A. HF

B. Ba(OH)₂

C. NH₃

D. HBr

E. H₃PO₄

Explanation:

HBr is a strong acid. Common strong acids include HCl, HBr, HI, HNO₃, HClO₄, and the first ionization of H₂SO₄. HF and H₃PO₄ are weak acids, and NH₃ is a weak base. Common strong bases include soluble group 1 hydroxides and the dissolved portions of Ca(OH)₂, Sr(OH)₂, and Ba(OH)₂. KBr and NaCl are salts, not strong bases; being ionic does not make a compound a base.

3 / 8

Which of the following is the reducing agent in the reaction below?

ZnO(s) + C(s) → Zn(s) + CO(g)

A. ZnO

B. C

C. Zn

D. CO

E. O

Solution:

Corrected calculation for question 543

4 / 8

Which statement about the following reaction is correct?
2KI + Cl₂ → 2KCl + I₂

A. Cl₂ is the oxidizing agent.

B. KCl is the reducing agent.

C. Cl is oxidized.

D. I is reduced.

E. A and B

Solution:

Corrected calculation for question 544

5 / 8

The oxidation number of P in HPO₄^2- is __________.

A. -1

B. -2

C. 0

D. +5

E. +7

Explanation:

In HPO₄²⁻, H has an oxidation number of +1 and O has an oxidation number of −2. If the oxidation number of P is x, then (+1) + x + 4(−2) = −2, so x = +5.

6 / 8

Which species has sulfur in the same oxidation state as sulfur in H₂SO₄?

A. S₂O₃^2-

B. MgSO₄

C. CdS

D. SO₃^2-

E. Na₂S

Solution:

Corrected calculation for question 546

Explanation:

Sulfur is +6 in H₂SO₄ and MgSO₄. In S₂O₃²⁻, +2 is the average sulfur oxidation state; the two sulfur atoms are inequivalent. Sulfur is −2 in CdS and Na₂S and +4 in SO₃²⁻.

7 / 8

What is the net ionic equation for the reaction between aqueous BaCl₂ and aqueous Na₂SO₄?

A. Ba²⁺(aq) + 2Cl^–(aq) + 2Na⁺(aq) + SO₄^2-(aq)

B. 2Cl^–(aq) + 2Na⁺(aq) → 2NaCl(aq)

C. BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s) + 2NaCl(aq)

D. Ba²⁺(aq) + SO₄^2-(aq) → BaSO₄(s)

E. Ba²⁺(aq) + 2Cl^–(aq) + 2Na⁺(aq) + SO₄^2-(aq) → BaSO₄(s) + 2Na⁺(aq) + 2Cl^–(aq)

Solution:

8 / 8

Balance the following net ionic reaction in acidic solution using the smallest whole-number coefficients. For each mole of Cr₂O₇²⁻, how many moles of water are produced and how many moles of chloride ions are consumed, respectively?

Cr₂O₇²⁻ + Cl⁻ → Cr³⁺ + Cl₂

A. 2 moles of water, 12 moles of chloride ion

B. 7 moles of water, 14 moles of chloride ion

C. 7 moles of water, 6 moles of chloride ion

D. 1 mole of water, 6 moles of chloride ion

E. 14 moles of water, 12 moles of chloride ion

Solution:

Completed balanced redox reaction: Cr₂O₇^2- + 14H⁺+ 6Cl^– → 2Cr³⁺ + 7H₂O + 3Cl₂

Step	Equations
Net ionic equation
Separate oxidation and reduction half-reactions
Balance all atoms except H and O
Balance O by adding H₂O
Balance H by adding H⁺
Balance charges by adding electrons
Multiply the half-reactions to cancel electrons
Cancel electrons and complete the balanced redox reaction

Your score is

The average score is 59%

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