Science Test

In chemical reactions, what does the principle of conservation of mass mean

• mass is not created or destroyed

• The total mass of the reactants is greater than the total mass of the products

• The total mass of the reactants is less than the total mass of the products.

• Matter is not changed.

The substances listed on the left side of a chemical equation are the

• products

• coefficents

• precipitates

• reactants

A student mixed two chemicals to allow them to react. The temperature before the reaction was 25 ° C. The  temperature after the reaction was 18° C. Which of the following is true?

• This is an endothermic reaction

• This is an exothermic reaction

Which of the following is NOT a correct inference that you can make about the burning of gasoline?

• Chemical bonds are broken and others are formed.

• the reaction is a physical change

• new substances are formed

• energy is released

A rapid reaction between oxygen and a fuel is known as

• combustion

• heat

• activation

• decomposition

What happens when chemical bonds break and new bonds form?

• a physical change

• a chemical reaction

• matter is destroyed

• surface area increases

Every chemical reaction involves a change in

• mass

• energy

• concentration

• state

 

The only sure evidence for a chemical reaction is

• the formation of a gas

• a color change

• the production of one or more new substances

• changes in properties

Anything that has mass and takes up space is considered

• matter

• energy

• atoms

• chemistry

A chemical reaction that absorbs energy in the form of heat is described as

• endothermic

• exothermic

• combustion

• unbalanced