HL chem S.1

Element

Make up all substances, cannot be chemically broken down into simpler substances, are one type of atom and multiple types of the same atom can be an element

Compound

Chemically bonded atoms in a fixed ratio (water, carbon dioxide)

Mixture

Mixture of elements OR compounds, physically combined in an UNfixed ratio

Two types of mixtures

Heterogenous and homogeneous

Mixture where all components are in the same phase + example

Heterogeneous, air, steel

Mixture where all components are in different phases or are immiscible + examples

Heterogeneous, oil and water, milk, blood

Ways to seperate mixtures

F-filtration

E/R-evaporation/recrystallization

S-separatory funnel

D/R-distillation/reflux

M-melting point determination

Which ways aren’t necessarily ways to separate mixtures

Distillation/reflux and melting point determination

Filtration

Separates and insoluble solid from a liquid by passing it through a filter. Filtrate goes through filter paper into the flask while residue is left on filter paper. Can also be done through vacuum filtering.

Evaporation and recrystallization

if one component is soluble in water, ethanol, or a nonpolar solvent such as hexane, mixture can be warmed to dissolve soluble component. Solution filtered to remove undissolved and solvent evaporated. Solid purified through recrystallization by dissolving in small amt. of heated solvent and left to crystalize

Why non-polar solvents for evaporation?

Weak intermolecular forces —→ low evaporation point

Are alloys mixtures or compounds

Mixtures-they are not chemically bonded