topic 2: states of matters and mixtures

Question 1

chlorination

Answer 1

a process used in water treatment where chlorine gas is injected into the water to kill any microbes

Question 2

chromatography

Answer 2

a process used to separate substances in a mixture. if the substance depends on distribution between a mobile phase and a stationary phase

Question 3

crystallisation

Answer 3

a separation technique to obtain soluble solids from solutions. the process involves heating the solution until crystals start to form, leaving the solution to cool and then filtering the formed crystals from the solution

Question 4

filtration

Answer 4

a separation technique used to separate an insoluble solid from a solution

Question 5

fractional distillation

Answer 5

a process used to separate a mixture of liquids. the liquids have different boiling points so can be separated into different fractions within a fractionating column

Question 6

gas

Answer 6

the state of matter where the particles have the most energy. the particles in a gas are relatively spread out and move randomly in all directions

Question 7

ground water

Answer 7

water which collects in rocks that then trap the water underground

Question 8

liquid

Answer 8

the state of matter where the particles are arranged randomly and close together. the particles are able to move past each other

Question 9

melting point data

Answer 9

data which can be used to evaluate the purity of a substance a pure substance should have a sharp melting point

Question 10

mixture

Answer 10

contains at least two different elements or compounds which are not chemically bonded together

Question 11

mobile phase

Answer 11

the fluid (gas or liquid) which moves through the chromatography system, carrying the mixture which is to be separated

Question 12

paper chromatography

Answer 12

a type of chromatography which uses paper as the stationary phase and a solvent as the mobile phase. the solvent carries the mixture up the paper where the substances in the mixture then separate, depending on how soluble they are in the mobile phase

Question 13

particle theory

Answer 13

the theory which models the three states of matter by representing particles as small solid spheres. particle theory can help explain melting, boiling, freezing and condensing

Question 14

potable water

Answer 14

water that is safe for humans to drink

Question 15

pure substance

Answer 15

the chemistry definition of a pure substance is a substance which contains only one compound or element. the everyday definition of a pure substance is a substance which has nothing added to it, eg. pure milk.

Question 16

rf value

Answer 16

a value used in chromatography which is calculated as the distance travelled by the dissolved substance divided by the distance travelled by the solvent, it can be used to identify substances within a mixture

Question 17

sedimentation

Answer 17

a process used in water treatment to remove solids from the water. suspended solids will fall to the bottom of the container and forma sediment, allowing them to be easily removed

Question 18

simple distillation

Answer 18

a separation technique used to separate a liquid from a solution. the solution is heated so that only the liquid with the lowest boiling point evaporates. this gas is then condensed in a condenser before being collected as a liquid

Question 19

solid

Answer 19

the state of matter where the particles hold a regular arrangement and have the least amount of energy

Question 20

state symbols

Answer 20

the symbols used in chemical equations to denote the states of the chemicals reaction: (s) - solid, (l) - liquid, (g) - gas, (aq) aqueous solution

Question 21

stationary phase

Answer 21

the none moving phase which the mobile phase passes over during chromatography

Question 22

waste water

Answer 22

water from industrial, domestic, agricultural and commercial activity. it requires treatment before it is potable.