properties of matter matter: anything that has mass and takes up space substance: matter that has a...
TRANSCRIPT
Properties of Matter
Matter: anything that has mass and takes up space
Substance: matter that has a uniform and unchanging composition.
An element is a substance that has only one kind of atom.
Gold A compound is a substance that has two or more types of atoms in fixed proportions.
Water (H2O)
Substances are identified by their...
Physical and Chemical properties
Substances are identified by their...
Physical and Chemical properties
Physical properties can be observed and measured WITHOUT permanently changing the material.
Observable physical properties:
Color, shape, hardness, odor, texturestate of matter (solid, liquid or gas)luster (how light reflects off of it)
Measurable physical properties:
Density-mass contained in 1 mL of
material
Melting point-Temperature at which
material begins to melt
Freezing point-Temperature at which
material begins to freeze
Boiling point-Temperature at which
material begins to boil
Chemical properties can only be observed or measured by PERMANENTLY CHANGING the material.
Examples:
Flammability, toxicity (how poisonous it is), acidity, radioactivity, reactivity with oxygen, light sensitivity
Physical Change Chemical Change
•melting •Light or flamegiven off
•boiling •Color/odor change
•evaporatingdissolving•Forming a solid
•freezing •Temperaturechange•grinding
•Gas bubblesformed•cutting
Chemical or physical change?
1. When heated, a substance goes from a liquid to a gas.
2. When heated, the color of a substance changes from blue to white.
3. When heated, a substance burns.
PHYSICAL!
CHEMICAL!
CHEMICAL!
Chemical or physical change?
4. When hit with a hammer, a substance explodes.
5. When hit with a hammer, a substance flattens.
6. When hit with a hammer, a substance breaks apart into smaller pieces.
CHEMICAL!
PHYSICAL!
PHYSICAL!
Chemical or physical change?
7. When water is added to a blue liquid, it changes to a lighter blue.
8. When a clear liquid is added to a blue liquid, a white solid is formed.
9. When water is added to a blue liquid, it forms a blue layer and a clear layer.
PHYSICAL!
CHEMICAL!
PHYSICAL!
Indicators of chemical change
• A color change
• Gas evolution (bubbles)
• Precipitate (solid) formation
• Temperature change
• Energy given off (light or flames)
Mixture: a combination of two or more substances.
The composition of mixtures is variable.
Uh oh!
Heterogeneous mixture: a mixture in which the physical properties are different in different parts of the mixture.
heterogeneous
Homogeneous mixture: a mixture in which the physical properties are the same throughout.
A solution
soluble dye
Types of solutions
Gas/gas
Gas/liquid
Liquid/liquid
Solid/liquid
Solid/solid
Air is 78% N2 and 21% O2
Carbonated sodas are made by dissolving CO2 gas in water
8 carat gold is a solid solution of Cu, Ag and Au
Vinegar is 5% acetic acid, 95% water
Sports drinks are 0.1% NaCl, 5% sugar and 94.9% water.
Colloids: very small particles are suspended in solution
Gold/silver alloy particles in glass
Water droplets in air
Tyndall Effect: Scattering of light off of colloidal particles
No Tyndall effect = not a colloid
Separating Mixtures
Mixtures can be separated by taking advantage of differences in physical properties.
Filtration: a porous barrier is used to separate a solid from a liquid.
The filter can only separate out particles of solid that are LARGER than the pores through the filter.
Distillation: separation of substances by differences in boiling point.
The substance with the lower boiling point will distill off first.
Crystallization: formation of a pure solid substance from a solution containing the dissolved substance.
Sodium acetate in water
p-dichlorobenzene in chloroform