Chemistry Middle School Review

When a scientist mixed two chemicals, an exothermic reaction takes place. Which of the following would be proof that the reaction was exothermic?

• a change of color
• a change of state
• a temperature decrease
• a temperature increase

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Which of the following is a chemical change?

• water freezes to form ice
• sugar dissolves in water
• gasoline burns in a car engine
• a piece of metal expands when it is heated

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

In the reaction methane + oxygen turns into carbon dioxide + water, the methane and oxygen are called _______________.

• reactants
• products
• neutrals
• energizers

Tags

NGSS.MS-PS1-5

A change in the shape of an object is an example of _________________.

• a chemical change
• energy
• an endothermic change
• a physical change

Increasing the concentration of a reactant in a chemical reaction will _____________.

• decrease the rate of the reaction
• stop the reaction from happening
• increase the rate of the reaction
• have no effect on the rate of the reacion

Tags

NGSS.HS-PS1-5

In any chemical reaction, the mass of the products is always:

• slightly less than the mass of the reactants
• much less than the mass of the reactants
• the same as the mass of the reactants
• greater than the mass of the reactants

Tags

NGSS.HS-PS1-7

Raising the temperature of a chemical reaction would make the reaction __________________.

• happen slower
• happen faster
• stop completely
• proceed as normal

Tags

NGSS.HS-PS1-5

What are substances on the left side of a chemical equation called?

• electrons

• groups

• products

• reactants

Tags

NGSS.HS-PS1-7

What is a chemical equation?

• a diatomic molecule

• a shorthand representation of a chemical bond

• a shorthand representation of a chemical reaction

• a substance

Tags

NGSS.MS-PS1-5

What does the number in front of the molecular symbol mean?

• It shows that there is only one molecule present in a reaction

• It shows the number of molecules in the reaction

• It shows the number of reactions that took place

• All of the choices

Tags

NGSS.HS-PS1-7