Chemical Reactions

A material used to decrease the rate of a chemical reaction...

• Fuel

• Enzyme

• Catalyst

• Inhibitor

Which describes a physical change?

• Milk left out developing an odor

• wood logs burning

• Coconut oil freezing after being placed in the freezer

• Elements mixed to form salt

Law of conservation of mass is true for...

• reactions in open systems only

• reactions in open and closed systems

• reactions in closed systems only

• no reactions

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What happens when a chemical bonds break and new bonds form?

• a chemical change

• matter is destroyed

• surface are increases

• a physical change

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A shorter way to show a chemical reaction, using symbols instead of words, is called a

• symbol

• subscript

• Chemical Equation

• chemical formula

which two of these are opposites?

• precipitate and synthesis reaction

• single replacement and double replacement

• decomposition and single replacement reaction

• synthesis and decomposition reaction

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

• unbalanced

• endothermic

• exothermic

• combustion

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which observation is the sign of a chemical change?

• a melting block of ice leaves a large puddle

• a marble statue breaks when it falls onto the floor

• a cloud changes shape when blown by the wind

• rotting potato gives off a bad smell

Tags

NGSS.MS-PS1-2

The minimum amount of energy needed to start a reaction is the ....

• endothermic energy

• chemical energy

• activation energy

• exothermic energy

what best describes the atoms involved in a reaction?

• the arrangement of atoms does not change

• three atoms are destroyed

• five atoms are formed in the reaction

• The number of atoms does not change

Tags

NGSS.MS-PS1-5