- The three states of matter are
- solid: close together in neat rows, vibrate, low energy
- liquid: close together, move around slowly, some energy
- gas: far apart, move around in random directions, high energy
- Changes of state: melting, evaporating, condensing, freezing, sublimation.
- For a change of state, particles need to move fast or slow enough to break or build the forces of attraction.
- Diffusion: spreading of particles in a gas or liquid with a net movement of particles from areas of high concentration to low concentration until uniform.
- Solute: the substance that dissolves.
- Solvent: the liquid in which it dissolves.
- Solution: the liquid formed.
- Saturated solution: is a solution into which no more solute can be dissolved.
- Solubility: maximum mass of a solute that dissolves in 100g of solvent.
- Practical: investigate the solubility of a solid in water at a specific temperature
- Element: The simplest type of substances made up of only one type of atom.
- Compound: Two or more elements chemically combined.
- Mixture: Two or more elements not chemically combined.
- Pure substances: have a fixed melting and boiling point, but that a mixture may melt or boil over a range of temperatures e.g. water 1000C.
- Simple distillation:
- Fractional distillation:
- Filtration:
- Crystallisation:
- Paper chromatography:
- Atom: An atom is the smallest part of an element.
- Molecule: A molecule is made of a fixed number of atoms covalently bonded together.
- Relative Charge: Proton (+1), Neutron (0), Electron (-1)
- Relative Mass: Proton (1), Neutron (1), Electron (0)
- Protons and neutrons are in the nucleus. Electrons are in the shells.
- On each element in the periodic table, the big number is the mass number and the smaller number is the proton number.
- Mass number: number of protons and neutrons.
- Proton number: number of protons.
- Isotope: atoms with the same number of protons but different number of neutrons.
- Relative atomic mass (Ar) = (mass x %) + (mass x %) + .../ 100%
- The periodic table is arranged in order of atomic number, in groups.
- Group number: the number of electrons in the outer shell, so elements in the same group have similar chemical properties
- e.g. Group 0 (or 8) elements are very unreative. They are called noble gases.
- 1st shell: up to 2 electrons, 2nd and 3rd Shell: up to 8 electrons.
- Metals: conduct electricity
- Non-metals: do not conduct electricity, have oxides, & they react with acids.
- Metals: left. Transition Metals: middle. Non-metals: right.
- Moles = Mass/ Mr.
- Atom economy = (Mr of desired products/ Mr of all products) x 100
- Percantage yield = (Actual Moles/ Expected Moles) x 100