Y10 MOCKS

Question 1

what is the change of state from solid -> liquid?heat

Answer 1

melting

Question 2

what is the change of state from liquid -> gas?

Answer 2

boiling/evaporation

Question 3

what is the change of state from gas -> liquid?

Answer 3

condensation

Question 4

what is the change of state from liquid -> solid?

Answer 4

freezing

Question 5

what is the change of state between solid and gas?

Answer 5

sublimation

Question 6

what is the energy change when melting?

Answer 6

heat taken in
energy is needed to break bonds between the particles in the solid

Question 7

what is the energy change when boiling?

Answer 7

heat taken in
energy is needed to break the bonds between the particles in the liquid

Question 8

what is the energy change when freezing?

Answer 8

heat given out
energy given out as particles bond together in the solid

Question 9

what is the energy change when condensing?

Answer 9

heat given out
energy given out as particles bond together in the liquid

Question 10

what are the main points of kinetic theory?

Answer 10

all matter is made of tiny, invisible, moving particles

the particles are constantly moving- the higher the temperature, the faster they move

heavier particles move more slowly than light ones at a given temperature

Question 11

what is diffusion in chemistry?

Answer 11

the mixing of atoms or molecules due to their continuous and random motion

Question 12

what is brownian motion?

Answer 12

the constant random movement of particles is caused by collision with air or water molecules which are themselves in continuous and random motion

Question 13

what experiments are used to examine the motion of particles?

Answer 13

experiments using gases diffusing

Question 14

what happens when ammonia and hydrochloric acid are put in a tube to investigate brownian motion?

Answer 14

ammonia moves further along the tube as the particles are lighter, so they move faster

Question 15

what is an atom?

Answer 15

the smallest part of an element that can exist or take part in a chemical change

Question 16

why do some elements form molecules?

Answer 16

in some gases, single atoms cannot exist on teir own at ordinary temperatures

Question 17

what is an element?

Answer 17

a pure substance made up of only one type of atom

Question 18

what is a compound?

Answer 18

a pure substance which contains 2+ elements that are chemically bonded together in a fixed proportion

Question 19

what is a mixture?

Answer 19

a group of substances that aren’t chemically bonded together

Question 20

what are the properties of a compound?

Answer 20

fixed properties

properties differ from those of the elements

cannot be separated into elements without a chemical reaction

there is usually an energy change when a compound is made from its elements

Question 21

what are the properties of a mixture?

Answer 21

proportions may vary

properties are simply those of the separate elements

can be separated by a physical change (e.g. melting)

no energy change when the elements are mixed

Question 22

what is a pure substance?

Answer 22

a substance that contains no other substances

Question 23

how does the melting point change in an impure substance?

Answer 23

they will then melt at a lower range of temperatures rather than a higher fixed one

Question 24

what separation technique is used for a solid and a liquid when the solid hasn’t been dissolved?

Answer 24

filtration

the liquid filtrate passes through and the undissolved solid residue stays on the paper

Question 25

what separation technique is used to get a solid out of a dissolved liquid and solid mixture?

Answer 25

evaporation place the solution in an evaporation basin and heat to evaporate away the solvent

Question 25

what separation technique is used to get a solid out of a dissolved liquid and solid mixture?

Answer 25

evaporation place the solution in an evaporation basin and heat to evaporate away the solvent

Question 26

what is the method for crystallisation?

Answer 26

the solution is heated until 2/3 of the water is evaporated away a hot saturated solution is formed, which is cooled and crystals are formed

Question 27

what separation technique is used to get a liquid in a dissolved solid and liquid solution?

Answer 27

distillation the solution is heated. the liquid evaporates and the vapour passes into a condenser where it cools and turns back into a liquid the solid remains in the flask as a residue

Question 28

what separation technique is used to separate 2 immiscible liquids

Answer 28

separating funnel when two liquids don’t mix, they can be separated by running off the denser liquid by opening the tap of a separating funnel (denser solvent at the bottom)

Question 29

what separating technique is used for 2 miscible liquids?

Answer 29

fractional distillation both liquids evaporate and the gases pass into a fractionating column. they are condensed and boiled many times. the vapour of the gas with the lower boiling point leaves the column first and passes into the condenser

Question 30

what separating techniques can be used for 2 solids?

Answer 30

dissolving and chromatography

Question 31

explain dissolving:

Answer 31

find a solvent that will dissolve one solid but not the other heating is often necessary filter, washing the residue on the filter paper with some of the solvent and dry it to obtain the second solid (currently a solution), evaporate the filtrate

Question 32

what is chromatography?

Answer 32

separating 2 solids when both dissolve in the same solvent find a solvent that will dissolve both solids and place 2 drops of it on the filter paper the more soluble liquid will move further the dissolved solids are now separated on the paper

Question 33

how can you calculate the Rf value?

Answer 33

distance travelled by the component ————————————————— distance travelled by the solvent

Question 34

what is a halogen displacement reaction?

Answer 34

W2 + 2X —> 2W + X2

Question 35

acid + metal hydroxide —>

Answer 35

salt + water H+ + OH- -> H2O

Question 36

acid + metal oxide —>

Answer 36

salt + water 2H+ + O2- -> H2O

Question 37

acid + carbonate —>

Answer 37

salt + water + carbon dioxide H+ + HCO3- —> H2O + CO2

Question 38

what is a precipitation reaction?

Answer 38

cation + anion —> precipitate +. -