chemistry unit 1 and 2

Metric Conversion

Base Unit has a factor of 0

Examples of base units: meter, gram, liter

Density

Mass per unit volume D=m/v. Physical property

Temperature conversion formula

K= C +273.15

Matter

Everything in the universe that has mass and volume

Mass

Measure of the amount of matter

Unit-grams

Pure Substances

Elements and compounds

Has a constant composition

Does not change from one sample to another

Mixture

• Homeogenous or heterogenous.

• made up of two or mote substances that can be separated by physical processes

Element

Cannot be broken down into simpler substances, all known elements on periodic table

Compound

Has 2+ elements

Allotrope

Different structural form of the same element

Different arrangements of atoms

Different physical properties aswell as different chemical properties.

Homogenous

Same uniform appearance and composition throughout, can’t see different parts of mixture

Example: coffee

Heterogeneous mixture

Has visibly different substances of phases

Diatomic element

A molecule composed of 2 of the same atoms

Examples:Hydrogen, nitrogen, oxygen

Physical property

Characteristic of a substance that can be observed or measured without changing identity of substance.

Physical change

No change in composition, no new substance is formed

Chemical formulas are the same

Includes all phase changes

Phases of matter

Solid, liquid, gas

Solid

Definite shape and volume

Liquid

No definite shape, definite volume

Gas

No definite shape or volume

Phase changes

Melting, freezing, vaporization, condensation, sublimation, deposition

Melting

Solid to liquid

Vaporization

Liquid to gas

Freezing

Liquid to solid

Condensation

Gas to liquid

Sublimation

Solid to gas

Deposition

Gas to solid

mixtures can be…

separated by differences in physical properties

Evaporation

Used for separating soluble solid from liquid . Salt can be separated from water.

magnet

Separates magnetic substance from non magnetic

Filtration

Used for separating insoluble solid from liquid

Chromatrophy

Separates dissolved substance based on polarity

Distillation:

used to separate liquid from liquid by differences in baking point

Chemical reaction

Reactants(starting substance) result in products (ending substance)

Atoms will be reordered in the product, different from reactants

Chemical Bonds may break or form

Products have different chemical+physically property

Why do Chemical changes happen?

Result of a chemical reaction

Chemical symbols

Represents one element

One capital letter and sometimes a lowercase letter too

Chemical formula

Shows elements in a compound and relative proportions of elements

Chemical properties

Can only be observed with chemical changes.

Signs of chemical changes

Change in color, formation of gas(fizzing), formation of precipate(solid in liquid), change in temperature, production of odor