Chem H unit 1+2

1-2

Pure Substance

Only one kind of molecule. Constant properties. Stays at boiling temperature.

Two kinds of pure substances

elements and compounds

Elements

can’t be broken down into simpler substances.

Compounds

Can be broken down into simpler substances/elements.

Two kinds of compounds

Ionic and Molecular

ionic compounds

metal + nonmetal. Made out of positive and negative ions. Solid at room temp and have high melting points.

Sulfate

SO4 (2-)

Nitrate

NO3-

Carbonate

CO3 (2-)

Ammonium

NH4+

Acetate

CH3COO-

Hydroxide

OH-

Always soluble

NH4, NO3, group 1, CH3COO

Soluble except with “bad metals”

Cl, Br, I