1.9 Chemical Analysis

A single element or compound not mixed with any other substance

Solid substance is heated, temperature increases until its melting point - the temperature remains constant while the substance melts even though it is still being heated The solid changes to a liquid, it’s temperature increasing until its boiling point - the temperature remains constant while the substance boils even though it is still being heated The liquid becomes a gas and its temperature increases

At fixed/specific temperatures - this can be used to distinguish substances from mixtures

Over a range of temperatures - has a lower melting point as the bonds between particle are weaker due to impurities disrupting regular lattice arrangement. more impure the lower the melting point - an impure liquid with a substance dissolved in it has a higher boiling point as the liquid molecules re more attracted to the dissolved substance - have a stronger bond. more impure the higher the boiling point

A mixture which has been designed as a useful product

Mixing together several different substances in carefully measured quantities to ensure the product has the required properties

Mixture of at least 2 elements, one being a metal eg 18 Carat gold

Drug with corn starch (binding) and lubricant (swallow) eg calpol

Mixture of nitrogen, phosphorus, potassium compounds eg NPK fertilisers

Dissolves in water

Does not dissolve in water

Soluble substance which dissolves

Liquid in which solute dissolves

Mixture of solute dissolved in a solvent

Liquids which mix eg alcohol and water

Liquids which don’t mix eg water and oil

Filtered solution

Solid which remains on the filter paper

Liquid that is collected in distillation

When a liquid is heated and changes state onto a gas

When a gas cools and changes state into a liquid

Separates an INSOLUBLE substance from a LIQUID eg sand and water - The filter paper holds back the solid particles (residue) while allowing the liquid (filtrate) to drip through

Separates a SOLUTE from a SOLVENT eg salt and water - the solution is gently heated until some solvent evaporates - this leaves behind a saturated solution, and when left to cool forms crystals (crystallisation)

Separates a SOLVENT from a SOLUTION eg water from salt water or ONE of TWO MISCIBLE LIQUIDS eg water and ethanol SEE NOTE!! - the solution is heated, solvent vapour cools and becomes a liquid in the condenser and drips into a beaker. the solute stays behind • the substance with the lowest boiling point will be distilled first if using miscible liquids with largely different boiling points • water must continue to move in and out of the condenser to ensure it is filled at all times • anti-bumping granules are added to the contents of the flask to promote smooth boiling NOTE if done using ethanol and water, the ethanol will evaporate first at 79 degrees but water will begin to evaporate too, meaning the ethanol distillate will be impure. To prevent the fractional distillation is used instead