Chemistry paper 1 T1

CHEMISTRY PAPER 1

Topic 1 - Atomic structure and the periodic table

Element: a single type of atom

Mixture: two or more elements not chemically bonded together

Compound: two or more elements chemically bonded together

The nucleus consists of protons and neutrons, and has a positive charge.

The nucleus is surrounded by electron shells, where the electrons are. These have a negative charge.

Particle            relative mass           relative charge

proton                    1                             +1

neutron                  1                               0

electron              negligable                     -1

Atomic number: no. protons

Mass number (always the bigger number): no. protons + no. neutrons

NEED TO KNOW THESE FORMULAS:

Carbon dioxide : CO2

Water: H20

Oxygen: O2

Hydrogen gas: H2

Nitrogen gas: N2

Ammonia: NH3

Hydrochloric acid: HCl

Sulfuric acid: H2SO4

Seperating mixtures:

Simple distillation: seperating a liquid from a solid if we want to keep the liquid

Method: place substances in flask, hold over bunsen burner, evapourate the liquid by heating, condense the vapour by cooling in a glass tube surrounded by a condenser (jacket full of circulating cold water that keeps it cool), liquid drips into beaker and solid is left in original flask

Filtration: seperating an insoluble solid from a liquid

Method: get a filter funnel and line it with filter paper before placing it over a beaker, pour your mixture through it, the liquid will go through into the beaker, the sold will get stuck at the filter paper

Crystallisation: seperating a soluble solid from a liquid

Method: heat the mixture until the liquid evapourates, either using a bunsen burner for faster results or allowing this to naturally happen, leaving behind crystals of the solid, 

Fractional distillation: seperating two or more different liquids of different boiling points

Method: place substances in flask, attach a fractionating column (column full of glass beads) and a thermometer, hold over bunsen burner…