Kinetic theory

changes of state, solubility and diffusion

solubility

a measure of how easily a solute can dissolve into a solvent

saturated

a mixture where a solvent has dissolved as much solute as it can at a given temperature

solute

something that dissolves

solvent

something that a solute dissolves into

insoluble

a substance which can’t be dissolved

solution

a substance formed when a solute dissolves into a solvent

name 2 factors that can affect how easily a solute can dissolve

stirring and temperature

what happens when a solid sample of a mixture is heated?

parts of it melt at different temperatures

a pure substance has a melting and boiling point

fixed

mixture

two or more elements or compounds that are not chemically joined together

evaporation

the change in state from liquid to gas

chromatography

a separating technique used to separate mixtures that have different solubilities

filtration

a separating method to separate an insoluble solid from a liquid

crystals

the regular shaped structure of a solid. These are seen when a solvent is evaporated from a solution

filter paper

the thick paper used in chromatography and filtration

boiling point

the specific point at which a substance changes in state from a liquid to a gas

filtration

crystallisation

crystallisation

used to separate a dissolved solid from a solution, when the solid is much more soluble in hot solvent than in cold

decanting

used to separate an insoluble solid from a liquid

separating funnel

separating funnel

used to separate liquids with different densities

chromatography

distillation

separates two liquids with different boiling points

distillation

fractional distillation

separates multiple substances with different boiling point

how does fractional distillation differ from distillation?

distillation separates two substances, fractional distillation separates many substances

fractional distillation

solid to liquid

melting

liquid to gas

evaporation

gas to liquid

condensation

liquid to solid

freezing

solid to gas/ gas to solid

sublimation

describe the arrangement of particles in a solid

particles are in a regular arrangement, touching each other and are vibrating.

describe the arrangement of particles in a liquid.

particles are in an irregular arrangement, they flow and mostly touch.

describe the arrangement of particles in a gas.

particles are in an irregular arrangement, they flow and are separate (don’t touch)

what does each spot on a chromatography practical represent?

a pure sample

why does each ink sample have several dots after the experiment?

a mixture contains several pure substances, which move different distances, so has several spots.

what does it mean if a chromatography spot travels a long distance?

substance is very soluble and has an affinity for the mobile phase

what does it mean if a chromatography spot travels a short distance?

substance is not very soluble and has an affinity for the stationary phase.

what does Rf stand for

retention factor

give the equation to find the Rf

Rf=distance travelled by pure substance / distance travelled by the solvent