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5 Chemical Reactions and Stoichiometry Online Quiz Questions

Use this free practice quiz with 20 questions to review 5 Chemical Reactions and Stoichiometry, test your knowledge, and prepare for your next test or exam.

20 questions
01
True or false
1 point

In the expression 2H2O2H_2O, the coefficient 22 counts two water entities, while changing a subscript would change the substance's composition.

  1. A

    True

  2. B

    False

02
Choose one
1 point

The reaction AgNO3+NaCl→AgCl+NaNO3AgNO_3 + NaCl \rightarrow AgCl + NaNO_3 follows which reaction pattern?

  1. A

    Synthesis

  2. B

    Double replacement

  3. C

    Decomposition

  4. D

    Combustion

03
Fill in the blank
1 point

For Ca(OH)2Ca(OH)_2, the number of oxygen atoms is and the number of hydrogen atoms is .

04
True or false
1 point

One mole of O2O_2 molecules contains two moles of oxygen atoms.

  1. A

    True

  2. B

    False

05
Written response
1 point

What is the term for the reactant that is consumed first and determines the maximum amount of product?

06
Choose one
1 point

Which equation correctly balances the combustion of propane using the smallest whole-number coefficients?

  1. A

    C3H8+5O2→3CO2+4H2OC_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O

  2. B

    C3H8+3O2→3CO2+4H2OC_3H_8 + 3O_2 \rightarrow 3CO_2 + 4H_2O

  3. C

    C3H8+5O2→CO2+4H2OC_3H_8 + 5O_2 \rightarrow CO_2 + 4H_2O

  4. D

    3C3H8+5O2→3CO2+4H2O3C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O

07
Written response
1 point

A pure water sample has a mass of 36.032 g36.032\ \mathrm{g}. Using a molar mass of 18.016 g/mol18.016\ \mathrm{g/mol}, how many moles of water are in the sample? Enter the numerical amount in mol.

08
Choose all
1 point

Which statements describe valid steps or rules for balancing a chemical equation? Select all that apply.

  1. A

    Adjust coefficients until each element has the same atom count on both sides.

  2. B

    Change coefficients only; do not change the formulas' subscripts.

  3. C

    Change a reactant's subscript whenever it helps match the atom counts.

  4. D

    Reduce the coefficients to the smallest whole-number ratio after balancing.

09
Fill in the blank
1 point

For every 2 mol2\ \mathrm{mol} of H2H_2 consumed in 2H2+O2→2H2O2H_2 + O_2 \rightarrow 2H_2O, the equation requires mol of O2O_2 and forms mol of H2OH_2O.

10
Choose one
1 point

Hydrogen reacts with excess oxygen according to 2H2+O2→2H2O2H_2 + O_2 \rightarrow 2H_2O. What mass of water can form from 4.00 g H24.00\ \mathrm{g}\ H_2, given molar masses of 2.016 g/mol2.016\ \mathrm{g/mol} for H2H_2 and 18.016 g/mol18.016\ \mathrm{g/mol} for H2OH_2O?

  1. A

    35.7 g H2O35.7\ \mathrm{g}\ H_2O

  2. B

    4.00 g H2O4.00\ \mathrm{g}\ H_2O

  3. C

    17.9 g H2O17.9\ \mathrm{g}\ H_2O

  4. D

    71.4 g H2O71.4\ \mathrm{g}\ H_2O

11
Choose all
1 point

When quantities of multiple reactants are given, which statements correctly describe how to identify the limiting reactant? Select all that apply.

  1. A

    Convert each reactant quantity to moles before using a mole ratio.

  2. B

    Use the balanced equation's mole ratios to calculate the amount of product each reactant could form.

  3. C

    Identify as limiting the reactant that could form the least product.

  4. D

    Identify as limiting whichever reactant has the smaller given mass.

12
Open ended
1 point

For 2H2+O2→2H2O2H_2 + O_2 \rightarrow 2H_2O, a mixture contains 4 mol H24\ \mathrm{mol}\ H_2 and 1 mol O21\ \mathrm{mol}\ O_2. Identify the limiting reactant and calculate the maximum amount of water that can form. Explain your reasoning using the mole ratios.

13
Choose one
1 point

How many moles of O2O_2 molecules are represented by 1.204428152×10241.204428152\times10^{24} O2O_2 molecules? Use NA=6.02214076×1023 mol−1N_A=6.02214076\times10^{23}\ \mathrm{mol^{-1}}.

  1. A

    2 mol O22\ \mathrm{mol}\ O_2

  2. B

    0.5 mol O20.5\ \mathrm{mol}\ O_2

  3. C

    4 mol O24\ \mathrm{mol}\ O_2

  4. D

    2 mol O atoms2\ \mathrm{mol}\ O\ atoms

14
Written response
1 point

What term describes the simplest whole-number ratio of ions represented by an ionic compound formula such as NaClNaCl?

15
Choose one
1 point

A pure sample contains 0.50 mol0.50\,\text{mol} of NaCl. Its molar mass is 58.44 g/mol58.44\,\text{g/mol}. What is the sample’s mass?

  1. A

    29.22 g

  2. B

    0.0086 g

  3. C

    58.44 g

  4. D

    116.88 g

16
Choose one
1 point

An ionic equation has matching counts of every element on both sides, but the total charge is +2+2 on the reactant side and +1+1 on the product side. Which conclusion is correct?

  1. A

    It is balanced because the atom counts match.

  2. B

    It is balanced if the products have more atoms than the reactants.

  3. C

    It is not balanced because the total charge differs.

  4. D

    It is balanced if the formulas of the products are unchanged.

17
Choose one
1 point

A chemist is checking whether a reaction is redox. Which observation identifies a redox reaction?

  1. A

    The reaction produces a gas.

  2. B

    The oxidation state of an element changes.

  3. C

    The atom counts differ between the two sides.

  4. D

    The substances are dissolved in water.

18
Choose one
1 point

Which observation is a possible outcome of a double-replacement reaction in aqueous solution?

  1. A

    A precipitate forms.

  2. B

    The nuclei of the atoms change.

  3. C

    The reactants become different elements.

  4. D

    The total number of atoms increases.

19
True or false
1 point

A reaction can be described as both combustion and redox; classifying it as combustion does not rule out classifying it as redox.

  1. A

    True

  2. B

    False

20
Written response
1 point

Using atomic molar masses of 1.008 g/mol1.008\,\text{g/mol} for hydrogen and 16.00 g/mol16.00\,\text{g/mol} for oxygen, calculate the molar mass of H₂O.