Unit 1 matter and physical chemical changes NOTES

Matter: anything that has mass and takes up space Mass – the amount of matter in something. Volume – the amount of space something

occupies.

Weight = amount of matter + Effect of Gravity

Reviewing MATTER

Matter, Mass, and Weight

Do you think you would weigh the same if you stood on the surface of the planet, Mercury?

Mercury is the smallest planet, and the planet closest to the sun. The gravity of Mercury is 38% of Earth's gravity. To calculate your weight on Mercury, multiply your weight by 0.38.

Matter Classification

Matter Flowchart

Pure Substances

Mixtures

A. Matter Flowchart

MATTER

Can it be physically separated?

Homogeneous Mixture

(solution)

Heterogeneous Mixture Compound Element

MIXTURE PURE SUBSTANCE

yes no

Can it be chemically decomposed?

noyesIs the composition uniform?

noyes

Colloids Suspensions

A. Matter Flowchart

Examples:

graphite

Trail Mix

sugar (sucrose-

C12H22O11)

paint

soda

element

hetero. mixture

compound

hetero. mixture

solution

B. Pure Substances

Element composed of identical atoms EX: copper wire, aluminum foil

B. Pure Substances

Compound

composed of 2 or more elements in a fixed ratio

properties differ from those of individual elements

EX: table salt (NaCl)

B. Pure Substances

For example…

Two different compounds, each has a definite composition.

Law of definite proportions: Regardless of the amount, a compound is always composed of the same elements in the proportions by mass.

C. Mixtures

Variable combination of 2 or more pure substances.

Heterogeneous Homogeneous

C. Mixtures (Homogeneous)

Solution (homogeneous) Dissolving homogeneous very small particles No Tyndall effect

Tyndall Effect

particles don’t settle EX: rubbing alcohol

Tyndall Effect

Disperses / ScattersLight

C. Mixtures (heterogenous)

Colloid heterogeneous medium-sized particles Tyndall effect particles don’t settle EX: milk

C. Mixtures

Suspension heterogeneous large particles particles settle EX: sand and water

C. Mixtures

Examples:

Whipped Cream

muddy water

fog

saltwater

Italian salad dressing

colloid

suspension

colloid

solution

suspension

What is a property?

Property: a characteristic of a substance that can be observed

Physical Property

Examples:

• luster

• malleability: the ability to be hammered into a thin sheet

• ductility: the ability to be stretched into a wire

• melting point

• boiling point

• density

• solubility

• specific heat

•Mass

•Volume

•Length

•color

Special Physical Properties

Melting point: the temperature at which a substance changes from a solid to a liquid at a given pressure.

water = 0oC Boiling point: the temperature at

which a substance changes from a liquid to a gas at a given pressure.

water = 100oC

Chemical Properties

Chemical property: a property that can only be observed by changing the identity of the substance.

Examples:

•flammability

•ability to rust

•reactivity with vinegar

•The ability to NOT react

Physical Vs. Chemical Properties

1) The melting point of water is 00C.

2) Ethanol burns in the presence of oxygen.

3) Potassium explodes when placed in water.

4) Oil has a very high viscosity.

5) Gold does not react when placed in water.

6) Nonmetals are very brittle.

7) The density of aluminum is 2.70 g/mL

8) Iron rusts in our atmosphere.

Physical and Chemical Changes

Change: the act of altering a substance

Physical Change

Physical change: a change that occurs that does not change the identity of the substance Form Size State or phase Dissolving

Physical Change

Examples: Melting ice (change in state or phase)

Freezing Kool-aid (change in state or phase)

Tearing paper (change in form or size)

Boiling water (change in state or phase)

Chemical Changes

Chemical change: a change that occurs causing the identity of the substance to change Burning Digesting food Reacting with other substances

A chemical change is called a chemical reaction.

Chemical Changes Cont’d

Indicators of a chemical change:

Development of lightDevelopment of heatDevelopment of a gasColor changeFormation of a precipitate

Is it Physical or Chemical?

Change Physical Chemical

Melting cheese

Burning wood

Milk souring

Wadding up paper

Bicycle rusting