Chemical Reactions

Multiple Choice

Why is it important to understand chemical reactions in everyday life?

• Because they only occur in laboratories

• Because they help explain natural and industrial processes

• Because they are dangerous and should be avoided

• Because they are rare events

Multiple Choice

Which part of a chemical equation represents the reactants?

• The left side of the arrow

• The right side of the arrow

• The coefficients

• The subscripts

Multiple Choice

Which of the following best describes a decomposition reaction?

• A chemical change in which a single compound breaks down into two or more simpler products

• A chemical change in which one element replaces another in a compound

• A chemical change involving the exchange of ions between two compounds

• A chemical change in which a compound reacts with oxygen

Multiple Select

Which of the following statements about double-replacement reactions is/are correct?

• They involve the exchange of positive ions between two compounds

• Both products must be aqueous

• They usually produce a precipitate, gas, or molecular compound

• Both reactants must be elements

Fill in the Blanks

Combustion reactions almost always involve a hydrocarbon and

to produce carbon dioxide and water.

Multiple Choice

One element replaces another in a compound.

• Synthesis
• Combustion
• Single Replacement
• Double Replacement

Multiple Choice

Pb(NO₃)₂ --> PbO + NO₂ + O₂

• Synthesis (combination)
• Decomposition
• Single replacement
• Combustion

Multiple Choice

3KOH + H₃PO₄ --> K₃PO₄ + 3H₂O

• Combination

• Decomposition

• Single replacement

• Double replacement

Multiple Choice

According to the rules for balancing chemical equations, what should you do if you have an odd number of atoms on one side of the equation?

• Add more reactants

• Double all coefficients

• Remove products

• Change the subscripts

Fill in the Blanks

Indicate the respective coefficients needed to balance the chemical equation.

SiCl₄(s) + H₂O(l) → H₄SiO₄(s) + HCl(l)