48 Stoichiometry Practice Problems for DAT Exam Prep

IV. Stoichiometry and Solution questions

Stoichiometry practice problems

There are a total of 48 stoichiometry practice problems, which are important content-oriented in the summary part of this chapter. Approximately 1 minute is given per question in each test. After the test, if you press the “See Result” button, the results will be displayed along with the answer choices. Red marks indicate incorrect answers and green marks indicate correct answers. Explanations or solutions to the questions are displayed below each question.

STOICHIOMETRY AND SOLUTION TEST 1

1 / 20

What is the density when 32g of an unknown compound is contained in the 2cm edge of a cube?

A. 32 g/cm³

B. 16 g/cm³

C. 8 g cm³

D. 4 g/cm³

E. 2 g/cm³

Solution:

2 / 20

Which of the following has the highest density at STP?

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:

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:

5 / 20

What is the mass percentage of oxygen in Cu(NO₃)₂, approximately?

A. 9%

B. 26%

C. 43%

D. 51%

E. 65%

Solution:

6 / 20

40 g of Cl is found in 110 g of AgCl compound. What is the mass percentage of Ag in the compound?

A. 36.4%

B. 63.6%

C. 107.9%

D. 98.1%

E. 67.8%

Solution:

7 / 20

50g of SO₂ is to be dissolved in water. If the mass percentage of SO₂in the solution is 25%, then how many grams of water should be prepared?

A. 12.5g

B. 50.0g

C. 100.0g

D. 150.0g

E. 200.0g

Solution:

8 / 20

How many moles of calcium and oxygen each are found in 50g of CaCO₃?

A. 0.5mole of calcium, 1.5mole of oxygen

B. 0.5mole of calcium, 0.5mole of oxygen

C. 1.5mole of calcium, 1.5mole of oxygen

D. 1.2mole of calcium, 1.0mole of oxygen

E. 1.2mole of calcium, 3.6mole of oxygen

Solution:

9 / 20

How many molecules of carbon are in 120g of saccharin, C₇H₅NO₃S, approximately?

A. 2.8×10²⁴

B. 4.0×10²³

C. 6.0×10²³

D. 2.0×10²³

E. 1.2×10²⁴

Solution:

10 / 20

How many grams of glucose, C₆H₁₂O₆, are equal to 2 moles of glucose?

A. 90g

B. 180g

C. 360g

D. 400g

E. 460g

Solution:

Molecular mass of C₆H₁₂O₆

= 12×6+1×12+16×6

= 180g/mol

Grams of C₆H₁₂O₆

= 180g/mol × 2 mol

= 360g

11 / 20

If ZnCl₂ contains 2.1×10²⁴ atoms, what is the mass of zinc chloride?

A. 39 g

B. 135 g

C. 270 g

D. 473 g

E. 2.8 × 10²⁶ g

Solution:

12 / 20

If sodium oxide, Na₂O, contains 12 × 10²² atoms, which of the following is an INCORRECT statement?

A. The mass of Na₂O is 12.4 g.

B. The atoms of cation is 2.4×10²³.

C. The total moles of ions is 0.2.

D. The mass of O is 3.2g.

E. The atomic numbers of sodium oxide is equal to anion.

Solution:

13 / 20

Palladium, Pd, is one of the important metals for making PFM (porcelain fused metal) crowns in a dental laboratory. How many atoms are in 212g of Pd?

A. 3.0 × 10²³

B. 6.0 × 10²³

C. 1.2 × 10²⁴

D. 6.4 × 10²⁴

E. 1.2 × 10²⁵

Solution:

14 / 20

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

A. 14g

B. 28g

C. 42g

D. 56g

E. 64g

Solution:

15 / 20

Unknown compound is composed of 224g of iron and 96g of oxygen. What is the empirical formula for the unknown compound?

A. FeO₃

B. Fe₂O₆

C. Fe₂O₃

D. Fe₄O₆

E. Fe₃O

Solution:

16 / 20

Percent composition of an unknown compound is 43.4% Na, 11.3% C, and 45.3% O by mass. What is the empirical formula for the unknown molecule?

A. Na₂CO₃

B. Na₄CO₆

C. NaC₂O₃

D. Na₈C₂O₁₂

E. Na₂CO₆

Solution:

17 / 20

The empirical formula of Caproic acid is C₃H₆O. What is the molecular formula when the molecular weight of Caproic acid is 116 amu?

A. C₁H₂O_0.5

B. C₃H₆O

C. C₆H₁₂O₂

D. C₉H₁₈O₃

E. C₁₂H₂₄O₄

Solution:

Molecular mass of C₃H₆O:

12×3+6+16 = 58g/mol

Unknown constant x:

x × 58g/mol = 116 g/mol

x = 2

Molecular formula:

2× C₃H₆O = C₆H₁₂O₂

18 / 20

The molecular mass of an unknown compound is 58g/mol. Which of the following could be the empirical formula for the unknown compound?

A. C₄H₁₀

B. C₂H₅

C. C₂H₆

D. CH₃

E. C₂H₃

Solution:

19 / 20

Carbon is reacted with Fe₂O₃to produce iron. What is the sum of the product coefficient when the following equation is balanced?

Fe₂O₃ + C → Fe + CO₂

A. 2

B. 3

C. 5

D. 7

E. 9

Solution:

20 / 20

Butane is burned in air. What is the sum of the coefficient from the balanced equation for the reaction?

A. 4

B. 15

C. 18

D. 25

E. 33

Solution:

Your score is

The average score is 27%

STOICHIOMETRY AND SOLUTION TEST 2

1 / 20

180g of C₃H₈O reacted with an excess of O₂ produces 277.2g of CO2. What is the percent yield of CO₂?

2C₃H₈O + 9O₂ → 6CO₂ + 8H₂O

A. 70%

B. 75%

C. 80%

D. 85%

E. 90%

Solution:

2 / 20

If 67.2g of Fe reacts with 32.0g of O₂, how many grams of Fe₂O₃ are produced from the following equation?

4Fe + 3O₂ → 2Fe₂O₃

A. 43g

B. 52g

C. 80g

D. 96g

E. 172g

Solution:

3 / 20

How many grams of PH₃ are used to produce 54g of H₂O in the following reaction? (O₂is the excess reactant)

4PH₃ + 8 O₂ → P₄O₁₀+ 6H₂O

A. 17g

B. 34g

C. 51g

D. 60g

E. 68g

Solution:

4 / 20

How many grams of Cl₂are required to react with 280g of Si in the following reaction?

Si + 2Cl₂ → SiCl₄

A. 350g

B. 700g

C. 1400g

D. 2800g

E. 3500g

Solution:

5 / 20

How many g of MgCl₂is dissolved in 9g of water when the mass percent of MgCl₂ in the solution is 40%?

A. 3g

B. 6g

C. 9g

D. 12g

E. 15g

Solution:

6 / 20

400 mL of solution is created by dissolving 148 g of KCl in water. What is the molarity of the KCl solution?

A. 5 M

B. 10 M

C. 20 M

D. 185 M

E. 370 M

Solution:

7 / 20

How many g of aspirin, C₉H₈O₄, are prepared in 250mL of dichloromethane, CH₂Cl₂, to produce a 1.o M solution of aspirin?

A. 0.25 g

B. 25 g

C. 45 g

D. 90 g

E. 180 g

Solution:

8 / 20

300mL of 12M NaOH is dissolved in water to produce 4M NaOH solution. How much water is added?

A. 300 mL

B. 600 mL

C. 900 mL

D. 1200 mL

E. 1500 mL

Solution:

9 / 20

What is the molar concentration of oxygen in a 0.25M H₃PO₄ solution?

A. 0.25 M

B. 0.5 M

C. 0.75 M

D. 1.0 M

E. 4.0 M

Solution:

0.25M × 4 moles of oxygen = 1.0 M

10 / 20

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

A. 0.3 m

B. 1.5 m

C. 3.0 m

D. 4.5 m

E. 5.0 m

Solution:

11 / 20

400g of unknown compound is dissolved in 5kg of water. If the molality of the solution is 4m, which of the following is the unknown compound?

A. HF

B. NaOH

C. Ca(OH)₂

D. H₂SO₄

E. HI

Solution:

12 / 20

When 5.0M NaCl solution has a density of 1.09g/mL, what is the molality of this solution? (M.W. of NaCl = 58g/mol)

A. 3.50

B. 6.25

C. 10.40

D. 11.25

E. 15.50

Solution:

13 / 20

What volume of o.85M KOH(aq) is needed to neutralize 60mL of 0.35 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 molarity of a final solution of KOH when 30.0mL of water is added to 50.0mL of 12.5M KOH?

A. 7.8 M

B. 15.6 M

C. 20.8 M

D. 31.2 M

E. 41.6 M

Solution:

15 / 20

What is the final concentration of BaCl₂ when 80ml of 4M BaCl₂solution is diluted to 50ml of BaCl₂ solution?

A. 1.3M

B. 2.5M

C. 5.0M

D. 6.4M

E. 12.8M

Solution:

16 / 20

When 2.0M boric acid, H₃BO₃, neutralizes 750 mL of 5.0M sodium hydroxide, NaOH, what volume of boric acid is needed?

A. 312 mL

B. 625 mL

C. 938 mL

D. 1250 mL

E. 1875 mL

Solution:

17 / 20

What molarity of Mg(OH)₂ is required when 5 L of Mg(OH)₂ neutralizes 100 L of 15M HCl?

A. 1 M

B. 75 M

C. 150 M

D. 300 M

E. 600 M

18 / 20

What is the product from the reactant?

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)

Solution:

Pb(NO₃)₂(aq) + Na₂SO₄(aq)

Ion equation: Pb²⁺(aq) + 2NO₃^–(aq) + 2Na⁺(aq) + SO₄^2-(aq)

Products: → PbSO₄(s) +2NaNO₃(aq)

19 / 20

Which of the following is the 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

E. HF(aq) + KOH(aq) → H₂O(l) + KF(aq)

Solution:

20 / 20

Which of the following is an insoluble compound?

A. AgCl

B. H₂SO₄

C. NaI

D. CaCl₂

E. NaOH

Solution:

When a halide (Cl^–, Br^–, I^–) is bonded with Ag⁺, Hg₂⁺, or Pb²⁺, it becomes an insoluble compound.

Your score is

The average score is 23%

STOICHIOMETRY AND SOLUTION TEST 3

1 / 8

Which of the following is NOT dissociated in water?

A. CH₃COOH

B. KOH

C. C₁₂H₂₂O₁₁

D. HNO₃

E. KBr

Solution:

Alcohols (CH₃OH, CH₃CH₂OH) and organic compounds (C₁₂H₂₂O₁₁) are non-electrolytes in water.

2 / 8

Which of the following is the strong acid?

A. HF

B. Ba(OH)₂

C. NH₃

D. HBr

E. H₃PO₄

Solution:

Strong acids: HCl, HBr, HI, H₂SO₄, HNO₃, HClO₄

Weak acids: H₃PO₄, CH₃COOH, HF, HCN

Strong bases: LiOH, NaOH, KOH, Mg(OH)₂, Ca(OH)₂, Sr(OH)₂, KBr, NaCl, NaOH, ionic compounds

Weak bases: NH₃, CH₃NH₂

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:

4 / 8

Which of the following is correct for the following reaction?

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:

5 / 8

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

A. -1

B. -2

C. 0

D. +5

E. +7

Solution:

HPO₄^2- : O(-2), H(+1, bonded with a nonmetal)

(+1)×1 +P +(-2)×4 = -2

P = +5

6 / 8

Which of the following compounds has the same oxidation number of S as in H₂SO₄?

A. S₂O₃^2-

B. MgSO₄

C. CdS

D. SO₃^2-

E. Na₂S

Solution:

7 / 8

What is the net ionic equation from the following reactants?

BaCl₂(aq) + Na₂SO₄(aq) →

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

How many moles of water and chloride ion are needed to c0mplete the balanced redox reaction from the unbalanced net ionic equation?

Cr₂O₇^2- + 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 moles 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

Processing	Equations
Net ionic equation
Separation into oxidation and reduction
Balance atoms except H, O
Balance O by adding H2O
Balance H by adding H+
Balance charges by adding electrons
Multiply by coefficient to cancel electrons
Cancel electrons and complete the balanced redox reaction

Your score is

The average score is 30%

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