Changes in Matter

Part 3

Physical Change

changes its physical appearance

but not its composition

Physical Change

changes in a substance that do not involve a

change in the identity or chemical make-up of

the substance.

Physical Change

ex: Folding of paper, Breaking of glass,

Cutting of wood

Physical Change

All changes in the state of matter are

Enthothermic

mnemonic MES stands for Melting, Evaporation, Sublimation

absorbed

endothermic - heat energy is

Positive

endo change of enthalphy is

endothermic

conversion of ice to water

endothermic process

breaking bonds is also

released

exothermic heat energy is

negative

exothermic change in ethalphy is

exothermic

ex. water to ice

freezing, condensation, deposition

exothermic phase changes

forming bonds

exothermic process

Chemical Change

a substance is transformed into a chemically

different substance.

Chemical Change

a change in a substance that involves a

change in the identity or chemical make-up of

the substance.

chemical change - fermentation

process of sugar to alcohol

Nuclear Change

nuclear fusion & fission

nuclear fusion

two light nuclei combined together to form heavier nuclei.

Nuclear fission

splitting of a heavy, unstable nucleus into two lighter ones.

Melting is a __________.

Physical Change

Sublimation

Which of the following is an endothermic reaction?

A change in a substance that involves a change in

the identity or chemical makeup of the substance

Chemical change

Splitting of a heavy, unstable nucleus into two

lighter one

Nuclear fission

A negative change in enthalpy.

Exothermic