Chemical Chemical

ChangeChange

akaaka

Chemical Reactions

Chemical Reactions

Concept of ChangeConcept of Change

Change Change

an act of altering a an act of altering a substancesubstance

Phys

ical C

hange

Phys

ical C

hange

A change that occurs A change that occurs which which does not does not change the identity of change the identity of the substancethe substance

Sig

ns

of

a

Sig

ns

of

a

Phys

ical C

hange

Phys

ical C

hange Melting Ice

Melting Ice Freezing Kool-aid

Freezing Kool-aid Tearing paper

Tearing paperBoiling water

Boiling water

Chem

ical

Chem

ical

Changes

Changes

A change that occurs A change that occurs causing the identity of causing the identity of the substance to the substance to changechange

New substance is New substance is formedformed

Has different Has different propertiesproperties

Mass does not change Mass does not change (Law of Conservation (Law of Conservation of Matter)of Matter)

Indicators of a

Indicators of a Chemical Chemical ChangeChange

Chem

ical

Chem

ical

Change

Change

Light given offLight given off

Chem

ical

Chem

ical

Change

Change

Presence Presence of hotof hot

Presence Presence of coldof cold

Chem

ical

Chem

ical

Change

Change

Gas producedGas produced

bubbling or bubbling or fizzingfizzing

Chem

ical

Chem

ical

Change

Change

Solid Solid precipitateprecipitate

Chem

ical

Chem

ical

Change

Change

Color changeColor change

Chem

ical

Chem

ical

Change

Change

Odor given offOdor given off

Pewwwww!Pewwwww!

Chem

ical

Chem

ical

Change

Change

Smoke producedSmoke produced

Is it a chemical Is it a chemical change?change?

Decide if it is physical or chemicalDecide if it is physical or chemical

Then tell your reasonThen tell your reason

Sm

oke

, colo

r

Sm

oke

, colo

r change

change

and a

tem

pera

ture

and a

tem

pera

ture

change

changeA forest fire destroys

A forest fire destroys

acres of land. There is

acres of land. There is

a lot of smoke, and the

a lot of smoke, and the

trees turn to charcoal.

trees turn to charcoal.

ChemicalChemical

Wate

r turn

s bro

wn b

eca

use

Wate

r turn

s bro

wn b

eca

use

the co

coa is b

row

n

the co

coa is b

row

nWhen making hot

When making hot

cocoa, clear water

cocoa, clear water

turns brown when you

turns brown when you

mix the cocoa in

mix the cocoa in

PhysicalPhysical

no n

ew

substa

nce

form

ed

no n

ew

substa

nce

form

ed

(meltin

g(m

eltin

g ))

Ice cream melts after it

Ice cream melts after it

falls on the ground

falls on the ground

PhysicalPhysical

No n

ew

substa

nce

has

No n

ew

substa

nce

has

form

ed

form

ed

(condensa

tion)

(condensa

tion)

On a hot day water

On a hot day water

forms on the outside of

forms on the outside of

a cold glass of water

a cold glass of water

PhysicalPhysical

Colo

r change

Colo

r change

A raw egg gets cooked

A raw egg gets cooked

ChemicalChemical

Gas fo

rmatio

n

Gas fo

rmatio

nWhen Alka Seltzer is

When Alka Seltzer is

dropped into water it fizzes.

dropped into water it fizzes.

ChemicalChemical

the p

aper is ch

angin

g

the p

aper is ch

angin

g

colo

r beca

use

the cra

yon

colo

r beca

use

the cra

yon

is red.

is red.

Red crayon changes

Red crayon changes

w

hite paper to red

white paper to red

PhysicalPhysical

The b

ubble

s were

alre

ady

The b

ubble

s were

alre

ady

there

, just u

nder p

ressu

re in

there

, just u

nder p

ressu

re in

the b

ottle

the b

ottle

Soda fizzes, and bubbles

Soda fizzes, and bubbles

as you pour it in a glass

as you pour it in a glass

PhysicalPhysical

Colo

r change a

nd

Colo

r change a

nd

tem

pera

ture

change

tem

pera

ture

changeWhen you crack a glow stick,

When you crack a glow stick,

hydrogen peroxide mixes with

hydrogen peroxide mixes with

other chemicals, causing it to

other chemicals, causing it to

glow and warm up.

glow and warm up.

ChemicalChemical

Vid

eo t

ime

Vid

eo t

ime

Bill Nye