Particulate nature of matter

What is a homogenous mixture?

Uniform composition and properties

What is a heterogeneous mixture?

Non-uniform composition, properties are not the same throughout

What is solvation?

Where a solute dissolves in a solvent because solvent particles attract and surround the solute particles

When is filtration used?

To separate an insoluble solid from a mixture of solid and liquid or solution

When is crystallisation used?

To separate a dissolved solid from a solution where the solid is more soluble in hot solvent than cold solvent

When is recrystallisation used?

To purify an impure solid by dissolving it in hot solvent and allowing it to crystallise as the solution cools

When is simple distilation used?

To separate a solvent from a solute or a pure liquid from a mixture based on differences in boiling point

When is fractional distillation used?

To separate two or more liquids in a homogeneous mixture that have similar boiling points

When is paper chromatography used?

To separate dissolved substances in a mixture based on differences in solubility and adsorption (attraction) to the paper

Properties of a solid

• Fixed shape and volume

• Particles closely packed in a regular pattern

• Particles can only vibrate in place, do not move

• Lowest energy state of mass

Properties of a liquid

• Fixed volume but take the shape of the container

• Close together but randomly arranged

• Can slide past each other

• Medium density

• More energy than solids but less than gases

Properties of gases

• no fixed shape or volume (expand to fill container)

• widely spaced and randomly arranged

• move quickly in all directions

• can be compressed easily

• very low density

• particle motion = collisions = pressure

• highest energy state of matter

what is melting?

solid to liquid

what is freezing?

liquid to solid

what is vaporisation? (+2 types)

liquid to gas:

• boiling = throughout the liquid at a specific temperature

• evaporation = only at surface and takes place below boiling point

what is condensation?

gas to liquid

what is sublimation?

solid to gas

what is deposition?

gas to solid

when are state change graphs flat and when are they increasing/decreasing?

• flat during a change of state (eg melting)

• increasing/decreasing when a substance is heating up/cooling down

what are the top and bottom numbers on a chemical symbol?

• top = mass number

• bottom = atomic/proton number

what is an isotope?

an atom of the same element with the same number of protons and electrons but different numbers of neutrons

what electron transmission emits visible light?

electrons jumping from any higher energy level to n=2

what is the filling order of subshells?

1s2s2p3s3p4s3d4p

what is the shape of an s orbital?

spherical

what is the shape of a p orbital?

dumbbell shaped

what is the molecular formula?

the actual number and type of atoms in a molecule

what is the empirical formula?

the simplest whole number ratio of each element in a compound

dm³ to cm³?

multiply by 1000dm

dm³ to m³?

÷1000

mg to g

÷1000

what is avogadro’s law?

equal volumes of gases (under the same conditions) contain the same number of molecules

properties of ideal gases

• constant random motion

• no intermolecular forces

• all collisions are elastic (no Ke lost)

• temperature is directly proportional to average kinetic energy of its particles

why do we use low pressure and high temperature to study gases?

they behave similarly to ideal gases

what happens to real gases at high pressure?

particles are close together so their volume becomes significant

what happens to real gases at low temperatures?

attractions between molecules becomes significant, reducing frequency and force of collisions so lower pressure than predicted