Chemical Equations

Sodium (Na) and water (H₂O) undergo a chemical reaction that produces sodium hydroxide (NaOH) and hydrogen gas (H₂).

• 2Na + 2H₂O → 2NaOH + H₂

• 2Na + H₂ → 2NaOH + 2H₂O

• H2 + 2H2O → 2Na + 2NaOH

• 2Na + 2NaOH → 2H2O + H2

Zinc (Zn) combines with hydrogen chloride (HCl) to form hydrogen gas (H₂) and zinc chloride (ZnCl₂).

Which equation represents this chemical reaction?

• Zn + 2HCl → H₂ + ZnCl₂

• Zn → H₂ + ZnCl₂ + 2HCl

• 2HCl → H₂ + Zn + ZnCl₂

• ZnCl₂ + Zn → H₂ + 2HCl

Which two substances are reactants in the following chemical equation?

CO + H₂O → CO₂ + H₂

• CO

• H₂O

• CO₂

• H₂

This chemical equation represents a chemical reaction.

HCl + NaOH → NaCl + H₂O

Which two chemicals are products in the chemical reaction?

• H₂O

• NaCl

• HCl

• NaOH

Which two chemicals are products in the following chemical reaction?

PbO₂ + 4HCl → PbCl₂ + Cl₂ + 2H₂O

• PbCl₂

• Cl₂

• PbO₂

• HCl

This chemical equation represents a chemical reaction.

2HNO₃ + Na₂SO₃ → 2NaNO₃ + H₂O + SO₂

Which chemical is a reactant in the reaction?

• Na₂SO₃

• H₂O

• NaNO₃

• SO₂

A teacher wrote the following part of a chemical equation involving water (H₂O) and carbon dioxide (CO₂):

H₂O + CO₂ → ?

What is the most likely result of the chemical reaction represented by this equation?

• H₂CO₃

• HNO₃

• H₂Ca₃

• NaCl

The chemical equation for a chemical reaction begins as shown.

AgNO₃ + NaBr → ?

What is the most likely result of the chemical reaction represented by this equation?

• AgBr + NaNO₃

• NaBr + NaNO₃

• AgBr + NO₃

• NaBr + CO₃

This is the balanced chemical equation for a reaction between acetic acid (in vinegar) and sodium bicarbonate (in baking soda).

How does this balanced chemical equation represent the conservation of matter in the chemical reaction?

• The amount of matter on the left-hand side is the same as the amount of matter on the right-hand side.

• There are more compounds on the right-hand side than there are on the left-hand side.

• The coefficients are the same for each compound represented in the reactants and products.

• There are more carbon (C) atoms represented on the left-hand side than on the right-hand side.

This chemical equation is balanced.

F₂ + 2NaBr → 2NaF + Br₂

How does the balanced chemical equation show the conservation of matter in this chemical reaction?

• The number of F atoms in the reactants equals the number of F atoms in the products.

• There are more Br atoms in the reactants than in the products.

• The compound NaF is a substance that is different from the compound NaBr.

• There are fewer Na atoms in the reactants than in the products.