Stoichiometry Quizzes: Master Chemical Calculations

Question 1

In a chemical reaction, the ratio of the number of moles of reactants to the number of moles of products is determined by the:

Accepted Answer

Stoichiometric coefficients in the balanced chemical equation

Answer

Law of Conservation of Mass

Answer

Temperature and pressure of the reaction

Answer

Molarity of the reactants and products

Question 2

Which of the following is NOT a unit of mass?

Accepted Answer

Mole

Answer

Gram

Answer

Pound

Answer

Kilogram

Question 3

The SI unit for amount of substance is the:

Accepted Answer

Mole

Answer

Atom

Answer

Pound

Answer

Gram

Question 4

In the reaction 2H2 + O2 -> 2H2O, the mole ratio of hydrogen gas to oxygen gas is:

Accepted Answer

2:1

Answer

1:2

Answer

1:1

Answer

2:2

Question 5

The percent yield of a reaction is calculated by:

Accepted Answer

(Actual yield / Theoretical yield) x 100%

Answer

(Theoretical yield / Actual yield) x 100%

Answer

(Actual yield - Theoretical yield) x 100%

Answer

(Theoretical yield + Actual yield) x 100%

Question 6

In a neutralization reaction between a strong acid and a strong base, the products are:

Accepted Answer

Always water and a salt

Answer

Always a weak acid and a weak base

Answer

Always gases

Answer

Always solids

Question 7

Identify the non-limiting reactant in a reaction.

Accepted Answer

The reactant that is present in excess

Answer

The reactant that is completely consumed in a reaction

Answer

The reactant that determines the maximum amount of product that can be formed

Answer

The reactant that is present in stoichiometrically correct proportions

Question 8

Which of the following balanced equations represents the combustion of methane?

Accepted Answer

CH4 + 2O2 → CO2 + 2H2O

Answer

CH4 + O2 → CO2 + 2H2

Answer

2CH4 + O2 → 2CO2 + 2H2O

Answer

CH4 + 3O2 → CO2 + 2H2O

Question 9

The mole is a unit used to represent the amount of a substance. Which of the following is NOT a unit for mole?

Accepted Answer

Kilograms

Answer

Atoms

Answer

Molecules

Answer

Ions

Question 10

A balanced chemical equation represents the stoichiometric ratio between reactants and products. What does the coefficient in front of a chemical formula in a balanced equation represent?

Accepted Answer

The number of moles of that substance involved in the reaction

Answer

The molar mass of that substance

Answer

The volume of that substance

Answer

The concentration of that substance

Question 11

Which of the following factors does NOT affect the rate of a chemical reaction?

Accepted Answer

Identity of the experimenter

Answer

Concentration of reactants

Answer

Temperature

Answer

Surface area of reactants

Question 12

Which of the following is the limiting reactant?

Accepted Answer

The reactant that is completely consumed in a reaction

Answer

The reactant that is present in excess

Answer

The reactant that is not completely consumed in a reaction

Answer

The reactant with the lowest molecular weight

Question 13

In the reaction NaOH + HCl → NaCl + H2O, what is the mole ratio of NaOH to HCl?

Accepted Answer

1:1

Answer

1:2

Answer

2:1

Answer

2:2

Question 14

In the reaction 2Fe + 3Cl2 → 2FeCl3, if 10.0 g of Fe and 15.0 g of Cl2 are used, which reactant is limiting?

Accepted Answer

Fe

Answer

Cl2

Answer

FeCl3

Answer

Cannot be determined from the given information

Question 15

Which equation represents a balanced chemical equation?

Accepted Answer

CH4 + 2O2 → CO2 + 2H2O

Answer

CH4 + O2 → CO2 + 2H2O

Answer

2CH4 + 2O2 → CO2 + 2H2O

Answer

CH4 + 3O2 → CO2 + H2O

Question 16

Which statement correctly describes stoichiometry?

Accepted Answer

It involves the quantitative relationships between reactants and products in chemical reactions.

Answer

It deals with the qualitative relationships between elements and compounds.

Answer

It predicts the products of a chemical reaction.

Answer

It determines the rate of a chemical reaction.

Question 17

Which unit is used to express concentration?

Accepted Answer

Molarity

Answer

Density

Answer

Volume

Answer

Mass

Question 18

In a balanced chemical equation for the combustion of propane (C3H8), what is the mole ratio of propane to water produced?

Accepted Answer

1:2

Answer

1:1

Answer

1:3

Answer

2:1

Question 19

Which of the following is NOT a unit of molarity?

Accepted Answer

% (w/v)

Answer

mol/L

Answer

M

Answer

mmol/mL

Question 20

When 25.0 g of sodium (Na) reacts completely with chlorine gas (Cl2), what mass of sodium chloride (NaCl) is produced?

Accepted Answer

117.0 g

Answer

25.0 g

Answer

58.5 g

Answer

234.0 g

Question 21

Which of the following balanced chemical equations represents a synthesis reaction?

Accepted Answer

2Na + Cl2 -> 2NaCl

Answer

2H2 + O2 -> 2H2O

Answer

CaCO3 -> CaO + CO2

Answer

NH3 + HCl -> NH4Cl

Question 22

What is the empirical formula of a compound that contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?

Accepted Answer

CH2O

Answer

C2H4O

Answer

C3H6O

Answer

C4H8O2

Question 23

Which of the following is a strong electrolyte?

Accepted Answer

HCl

Answer

CH3OH

Answer

NH3

Answer

C6H12O6

Question 24

How do the empirical and molecular formulas of a compound differ?

Accepted Answer

The empirical formula shows the simplest whole-number ratio of elements, while the molecular formula shows the actual number of atoms.

Accepted Answer

The molecular formula is a multiple of the empirical formula, indicating the actual number of atoms in a molecule.

Answer

The empirical formula can be determined from the molecular formula, but not vice versa.

Answer

The molecular formula cannot be uniquely determined from the empirical formula alone.

Question 25

To accurately determine the number of moles of a substance, use the formula:

Accepted Answer

Moles = Mass (g) / Molar Mass (g/mol)

Answer

Moles = Volume (L) / Molarity (mol/L)

Answer

Moles = Mass (g) / Density (g/mL)

Answer

Moles = Volume (mL) / Mass (g)

Question 26

In a balanced chemical equation, the numerical coefficients in front of the reactants and products signify:

Accepted Answer

The number of moles of each reactant and product

Answer

The mass of each reactant and product

Answer

The volume of each reactant and product

Answer

The concentration of each reactant and product

Question 27

Identify the limiting reactant:

Accepted Answer

The reactant that determines the maximum amount of product that can be formed

Answer

The reactant that is completely consumed during a reaction

Answer

The reactant that is present in excess

Answer

The reactant that is not completely consumed during a reaction

Question 28

At room temperature, which of the following substances exists as a gas?

Accepted Answer

Oxygen (O2)

Answer

Sodium chloride (NaCl)

Answer

Iron (Fe)

Answer

Water (H2O)

Question 29

Identify the redox reaction:

Accepted Answer

CH4 + 2 O2 → CO2 + 2 H2O

Answer

2 H2 + O2 → 2 H2O

Answer

NaCl + AgNO3 → NaNO3 + AgCl

Answer

NaOH + HCl → NaCl + H2O

Question 30

Which of the following is NOT a key concept in stoichiometry?

Accepted Answer

Quantum mechanics

Answer

Conservation of mass

Answer

Mole relationships

Answer

Avogadro's number

Question 31

What unit is used to express the concentration of a solution in terms of moles per liter?

Accepted Answer

Molarity (M)

Answer

Molality (m)

Answer

Normality (N)

Answer

Percentage (%)

Question 32

In a titration experiment, what is the purpose of using an indicator?

Accepted Answer

To signal the endpoint of the titration

Answer

To determine the exact volume of titrant added

Answer

To increase the reaction rate

Answer

To neutralize the analyte

Question 33

Which of the following units is NOT used to measure mass in chemistry?

Accepted Answer

milliliter

Answer

gram

Answer

pound

Answer

kilogram

Question 34

What is the molar mass of sodium chloride (NaCl)?

Accepted Answer

58.5 g/mol

Answer

23 g/mol

Answer

35.5 g/mol

Answer

12.5 g/mol

Question 35

In NaCl, the mole ratio of sodium to chlorine is:

Accepted Answer

1:1

Answer

1:2

Answer

2:1

Answer

3:1

Question 36

Which of the following is NOT a characteristic of a limiting reactant?

Accepted Answer

Present in excess

Answer

Present in the smallest mole ratio

Answer

Completely consumed in the reaction

Answer

Determines the maximum amount of product formed

Question 37

Which stoichiometric coefficient balances the equation: 2Fe + __O2 -> Fe2O3?

Accepted Answer

4

Answer

1

Answer

2

Answer

3

Question 38

Which of the following is a **strong electrolyte**?

Accepted Answer

NaCl

Answer

Sugar

Answer

NH3

Answer

CO2

Question 39

In a balanced chemical equation, the coefficients in front of each chemical formula indicate the:

Accepted Answer

Number of moles of each compound involved in the reaction

Answer

Number of atoms of each element present in the molecule

Answer

Mass of each compound involved in the reaction

Answer

Volume of each gas involved in the reaction

Question 40

Which of the following is NOT a mole-to-mole ratio?

Accepted Answer

25 grams of NaCl to 143.5 grams of AgCl

Answer

1 mole of H2 to 2 moles of O2

Answer

2 moles of HCl to 2 moles of NaCl

Answer

1 mole of glucose (C6H12O6) to 6 moles of CO2

Question 41

Which of the following is NOT a quantitative observation?

Accepted Answer

The solid is blue in color

Answer

The density of the liquid is 1.2 g/mL

Answer

The temperature of the gas is 25°C

Answer

The mass of the precipitate is 5.0 grams