Matter and Change

Part 2 – Changes in Matter

TAKS Student Expectation

11.8 Integrated Physics and Chemistry (8) Science Concepts. The Student knows that changes in matter affect everyday life. The student is expected to:(A) distinguish between physical and

chemical changes in matter such as oxidation, digestion, changes in state and in the rock cycle

Here’s what you have to do if you want to pass this part of

the TAKS:

1. Look at an observed change and know if it was physical or chemical.

2. Know what the heck a rock cycle is!

3. Know what “oxidation” means.

4. Understand the basic ideas of digestion.

Here’s what you have to do if you want to pass this part of

the TAKS:

1. Look at an observed change and know if it was physical or chemical.

2. Know what the heck a rock cycle is!

3. Know what “oxidation” means.

4. Understand the basic ideas of digestion.

Physical ChangeA change in the physical appearance of a

substance that does not change the identity of the substance.

LIQUID

SOLID

GAS

Physical ChangesPhase Change – physical change from

one state to another

LIQUIDBetween 0°C and

100 0°C

SOLIDBelow 0°C

GASAbove 100°C

Only the temperature changes

Still H2O in every form!!!

Physical Changes• Examples of physical changes:

Crushing an aluminum can

Cutting your hair

Shredding paper

Sample Question

Source: Spring 2006 TAKS

Chemical ChangesChemical changes, or chemical reactions,

occur when one or more substances is converted into another substance.

• Original atoms are preserved

• New substances are formed

• Different chemical composition than original substance

Chemical ChangesChemical changes are chemical

reactions.

Indicated by a number of signs• formation of a gas, • formation of a solid, or precipitate• change in temperature• evolution of heat and light• Change in color• Change in odor

Chemical Changes• When iron (Fe)

rusts, you can see it happen over a long period of time.

• The actual iron molecules change their structure as they react with oxygen and are oxidized.

Chemical Changes• Examples of chemical changes:

Grass growing

Frying an egg

Sample Question

Source: Spring 2004 TAKS

The Rock Cycle

• Lets Look at each part of the rock cycle and – Which areas involve

chemical change?– Which areas involve

physical change?

Sample Question

Source: Spring 2004 TAKS

Sample Question

Source: Spring 2003 TAKS

Digestion

• Lets Look at each part of the digestion– Which areas involve chemical

change?– Which areas involve physical

change?

Sample Question

Source: Spring 2004 TAKS