Principles of chemistry Revision
(a) States of matter
1.1-
Solid
Arrangement: Particles are close together and regularly packed.
Movement: Particles vibrate around a fixed point.
Energy: Particles have less kinetic energy than both liquids and gasses.
Liquid
Arrangement: Particles are close together but irregular.
Movement: Particles are free to move.
Energy: Particles have less kinetic energy than gasses but more than solids.
Gases
Arrangement: Particles are far apart and there are no forces between them.
Movement: Particles are free to move.
Energy: Particles have more kinetic energy than liquids and solids.
1.2-
1.3-
Diffusion is the random movement of particles. When particles diffuse, they spread out and mix with other
particles.
Particles move from an area of high concentration to low concentration.
Diffusion only occurs in gases and liquids as the particles are free to move.
Example of an experiment: water and potassium permanganate. The potassium permanganate diffuses through
the small gaps between the liquid and eventually turns all the liquid purple.
1.4-
the substance that dissolves is called the solute.
the liquid in which it dissolves is called the solvent.
the liquid formed is a solution.
a saturated solution is a solution into which no more solute can be dissolved.
1.5c-
Solubility is defined in terms of the maximum mass of a solute that dissolves in 100g of solvent. The mass
depends on the temperature.
1.6c-
The solubility of solids changes as temperature changes. This can be plotted on a solubility curve.
1.7c-
massOfsolute
Solubility(g/100g) = x 100
massOfsolution
(b) Elements, compounds and mixtures
, 1.8 –
Element: The simplest type of substances made up of only one type of atom.
Compound: A substance that contains two or more elements chemically joined together.
Mixture: Different substances in the same space, but not chemically combined.
1.9 –
Pure substances have a sharply defined melting point, e.g., 100% gold melts at 1036 oC.
Impure substances/mixtures have a temperature range over which they melt, e.g., yellow gold (75% gold, 10%
silver, 15% copper) melts from 915-963oC.
1.10 –
Simple distillation
This method is used to separate a liquid from a
solution. For example: separating water from salt
water. The salt water is boiled. The water vapour
condenses back into a liquid when passed through the
condenser. The salt is left behind in the flask.
(a) States of matter
1.1-
Solid
Arrangement: Particles are close together and regularly packed.
Movement: Particles vibrate around a fixed point.
Energy: Particles have less kinetic energy than both liquids and gasses.
Liquid
Arrangement: Particles are close together but irregular.
Movement: Particles are free to move.
Energy: Particles have less kinetic energy than gasses but more than solids.
Gases
Arrangement: Particles are far apart and there are no forces between them.
Movement: Particles are free to move.
Energy: Particles have more kinetic energy than liquids and solids.
1.2-
1.3-
Diffusion is the random movement of particles. When particles diffuse, they spread out and mix with other
particles.
Particles move from an area of high concentration to low concentration.
Diffusion only occurs in gases and liquids as the particles are free to move.
Example of an experiment: water and potassium permanganate. The potassium permanganate diffuses through
the small gaps between the liquid and eventually turns all the liquid purple.
1.4-
the substance that dissolves is called the solute.
the liquid in which it dissolves is called the solvent.
the liquid formed is a solution.
a saturated solution is a solution into which no more solute can be dissolved.
1.5c-
Solubility is defined in terms of the maximum mass of a solute that dissolves in 100g of solvent. The mass
depends on the temperature.
1.6c-
The solubility of solids changes as temperature changes. This can be plotted on a solubility curve.
1.7c-
massOfsolute
Solubility(g/100g) = x 100
massOfsolution
(b) Elements, compounds and mixtures
, 1.8 –
Element: The simplest type of substances made up of only one type of atom.
Compound: A substance that contains two or more elements chemically joined together.
Mixture: Different substances in the same space, but not chemically combined.
1.9 –
Pure substances have a sharply defined melting point, e.g., 100% gold melts at 1036 oC.
Impure substances/mixtures have a temperature range over which they melt, e.g., yellow gold (75% gold, 10%
silver, 15% copper) melts from 915-963oC.
1.10 –
Simple distillation
This method is used to separate a liquid from a
solution. For example: separating water from salt
water. The salt water is boiled. The water vapour
condenses back into a liquid when passed through the
condenser. The salt is left behind in the flask.
