1.1 Particulate Nature of Matter

Question 1

what are pure substances

Answer 1

substances made up of one type of substance and have a fixed composition
examples: elements and compounds.

Question 2

what are mixtures

Answer 2

2 or more substances combined together; don’t have a fixed composition.

Question 3

elements description

Answer 3

simplest forms of matter - consisting of only one type of atom. Cannot be chemically broken down into simpler substances.

Question 4

compounds description

Answer 4

pure substances composed of 2 or more different elements combined in fixed ratios.
Atoms are chemically bonded, so cannot be separated using physical methods.

Question 5

mixtures description

Answer 5

not pure substances, but contain pure substances. Composed of two or more elements or compounds in no fixed ratio.
not chemically bonded, so can be separated by physical methods.
components retain their individual properties.
Can be homogeneous or heterogeneous.

Question 6

what is homogeneous

Answer 6

type of mixture that has a uniform composition and no visible phases or boundaries.

Question 7

what is heterogeneous

Answer 7

type of mixture with a non-uniform composition with visible phases or boundaries.

Question 8

solute

Answer 8

substance that dissolves in solution

Question 9

solvent

Answer 9

substance in which other substances are able to dissolve

Question 10

solvation

Answer 10

interaction of a solvent with molecules or ions of a solute

Question 11

soluble vs insoluble

Answer 11

dissolves vs doesn’t dissolve

Question 12

filtration

Answer 12

separation of an insoluble solid from a liquid/ solution. Poured through filter paper and filter funnel. The filtrate (liquid) passes through and the residue (solid) remains in the paper.

Question 13

evaporation

Answer 13

separation of mixtures with a dissolved solute in a solvent. Solution is heated in evaporating dish and solvent evaporates, leaving the solute behind.

Question 14

solvation

Answer 14

separation of a heterogeneous mixture of two solids based on differences in solubility (one soluble, other insoluble).

Question 15

distillation

Answer 15

separation of a liquid mixture based on differences in volatility between components. The liquids are miscible and they are separated by one evaporating and the other not. It passes through the condenser, which condenses the gas back into a liquid to be collected in a flask.

Question 16

paper chromatography

Answer 16

separates a mixture os solutes in a solvent. The mixture is dissolved in a solvent. Mobile phase (when solution is undergoing chromatography). The chromatography paper is placed in the solution. Stationary phase. Components move through the stationary phase at different rates due to differences in solvation. Components with greater affinity to mobile phase have greater interaction with solvent and and move up further in the paper.

Question 17

Recrystallisation

Answer 17

removes impurities that are mixed in with a solid. uses varied solubilities of solida at different temperatures to separate them. the impure mixture is dissolved in hot solvent. insoluble impurities can be filtered off. solution is cooled, and the solubility decreases. the desired product forms crystals, and the soluble impurities are left in solution, which is then filtered. purification of the solid is carried out.