Chemical Reactions 7th Grade

What is a chemical reaction?

• A chemical reaction is a change in temperature.

• A chemical reaction is a physical change in matter.

• A chemical reaction is a biological process.

• A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.

Give an example of a chemical reaction.

• Baking a cake

• Iron rusting

• Photosynthesis in plants

• Water boiling

What are the reactants in a chemical reaction?

• The catalysts involved

• The temperature of the reaction

• The products of the reaction

• The substances that undergo a chemical change.

What are the products in a chemical reaction?

• Byproducts of the reaction

• Initial reactants

• Substances formed after the reaction

• Unrelated compounds

Explain the Law of Conservation of Mass in relation to chemical reactions.

• The Law of Conservation of Mass states that mass can be created or destroyed in chemical reactions.

• The Law of Conservation of Mass only applies to solid substances in reactions.

• In chemical reactions, the total mass of the reactants is equal to the total mass of the products.

• In chemical reactions, the total mass of the reactants is less than the total mass of the products.

What is a catalyst in a chemical reaction?

• A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.

• A catalyst is a substance that changes color during a chemical reaction

• A catalyst is a substance that is consumed in a chemical reaction

• A catalyst is a substance that slows down a chemical reaction

Differentiate between exothermic and endothermic reactions.

• Exothermic reactions are slower than endothermic reactions

• Endothermic reactions release energy

• Exothermic reactions absorb energy

• Exothermic reactions release energy, while endothermic reactions absorb energy.

What is a chemical equation?

• A chemical equation is a mathematical equation involving chemical symbols.

• A chemical equation is a representation of a physical equation in chemistry.

• A chemical equation is a diagram showing the structure of a chemical compound.

• A chemical equation is a symbolic representation of a chemical reaction.

Balance the following chemical equation: H2 + O2 -> H2O

• H2O -> H2 + O

• H2 + O2 -> 2H2O

• H2O2 -> H2 + O2

• H2 + O2 -> H2O2

Tags

CCSS.7.RP.A.2

Explain the difference between a physical change and a chemical change.

• In physical changes, the substance remains the same chemically, while in chemical changes, new substances are formed.

• Physical changes are reversible, while chemical changes are not.

• Physical changes always involve a change in state, while chemical changes do not.

• Physical changes involve a change in color, while chemical changes do not.