Read_Chemical Reactions and Equations

What is a chemical reaction?

• A process where substances change into new substances with different properties

• A process where substances remain unchanged

• A process where energy is not involved

• A process where only physical changes occur

Which of the following is evidence of a chemical reaction?

• Change in temperature

• Change in color

• Formation of a solid from two clear liquids

• All of the above

What does a balanced chemical equation ensure?

• The law of conservation of mass is obeyed

• The substances present are changed

• The reaction releases energy

• The reaction absorbs energy

What happens when ionic compounds dissolve in water?

• Their ions separate

• They form a precipitate

• They release energy

• They absorb energy

What is a synthesis reaction?

• Two substances combine to form one new product

• A single compound breaks apart into simpler substances

• A substance reacts with oxygen and releases energy

• Two aqueous ionic solutions are mixed

What is the role of water molecules in reactions in aqueous solutions?

• They act as the solvent

• They directly participate in the reaction

• They form precipitates

• They release energy

Which type of reaction involves the exchange of cations and anions between two aqueous ionic solutions?

• Double-replacement reaction

• Single-replacement reaction

• Decomposition reaction

• Combustion reaction

Which of the following best describes a combination (synthesis) reaction?

• A reaction where two or more substances combine to form a single product.
• A reaction where two substances react without forming a new product.
• A reaction that involves the exchange of ions between two compounds.
• A reaction where a single substance breaks down into two or more products.

Which equation represents a combination reaction?

• A + X → AX
• AX + X → A
• A + B → AB
• A + BX → AX

Which of the following substances must always be a reactant in a combustion reaction?

• Oxygen gas
• Nitrogen gas
• Carbon dioxide
• Methane