C5: chemical changes

Question 1

what does reactivity mean

Answer 1

how vigorously a substance chemically reacts

Question 2

how can metals be ordered by their reactivity

Answer 2

by comparing their reactions with water, acid, or oxygen

Question 3

what name is given to a list of metals ordered by their reactivity

Answer 3

reactivity series

Question 4

in terms of electrons, what makes some metals more reactive than others

Answer 4

they lose their outer shell electrons more easily

Question 5

why are gold and silver found naturally as elements in the earth’s crust

Answer 5

they are very unreactive

Question 6

what is an ore

Answer 6

rock containing enough of a metal compound to be economically worth extracting

Question 7

how are metals less reactive than carbon extracted from their ores

Answer 7

reduction with carbon

Question 8

in terms of oxygen, what is oxidation

Answer 8

addition of oxygen

Question 9

in terms of oxygen what is reduction

Answer 9

removal of oxygen

Question 10

why can metals like potassium and aluminium not be extracted by reduction with carbon

Answer 10

because they are more reactive than carbon

Question 11

how are metals more reactive than carbon extracted from their ores

Answer 11

electrolysis

Question 12

what is a displacement reaction

Answer 12

a more reactive substance takes the place of a less reactive substance in a compound

Question 13

what is an ionic equation

Answer 13

equation which gives some substances as ions and has spectator ions removed

Question 14

what type of substance is given as ions in an ionic equation

Answer 14

ionic compounds in solution

Question 15

what is a spectator ion

Answer 15

ion that is unchanged in a reaction

Question 16

what is a half equation

Answer 16

equation that shows whether a substance is losing or gaining electrons

Question 17

in terms of electrons what is oxidation

Answer 17

loss of electrons

Question 18

in terms of electrons what is reduction

Answer 18

gain of electrons

Question 19

in terms of pH what is an acid

Answer 19

a solution with a pH of less than 7

Question 20

in terms of pH what is a neutral solution

Answer 20

a solution with a pH of 7

Question 21

in terms of H+ ions what is an acid

Answer 21

a substance that releases H+ ions when dissolved in water

Question 22

how is the amount of H+ ions in a solution related to it’s pH

Answer 22

the more H+ ions, the lower the pH

Question 23

what are the names and formulae of three main acids

Answer 23

hydrochloric acid,HCl, sulfuric acid,H₂SO₄, nitric acid, HNO₃

Question 24

how do you measure the pH of a substance

Answer 24

universal indicator or pH probe

Question 25

what is a strong acid

Answer 25

an acid where the molecules or ions completely ionise in water

Question 26

what is a weak acid

Answer 26

an acid where the molecules or ions partially ionise in water

Question 27

what is a salt

Answer 27

compound formed when a metal ion takes the place of a hydrogen ion in an acid

Question 28

which type of salts fo sulfuric acid, hydrochloric acid and nitric acid acid form

Answer 28

sulfates,chlorides,nitrates

Question 29

what are the products of a reaction between a metal and an acid

Answer 29

salt + hydrogen

Question 30

what are the products of a reaction between a metal hydroxide and an acid

Answer 30

salt + water

Question 31

what are the products of a reaction between a metal oxide and an acid

Answer 31

salt + water

Question 32

what are the products of a reaction between a metal carbonate and an acid

Answer 32

salt + water + carbon dioxide

Question 33

what is a base

Answer 33

substance that reacts with acids in neutralisation reactions

Question 34

what is an alkali

Answer 34

substance that dissolves in water to form a solution above pH 7

Question 35

what is a neutralisation reaction

Answer 35

a reaction between an acid and a base to produce water

Question 36

what is the ionic equation for a reaction between an acid and an alkali

Answer 36

H⁺(aq) + OH⁻(aq) → H₂O(l)

Question 37

how do you obtain a solid salt from a solution

Answer 37

crystallisation

Question 38

when an acid reacts with a metal, which species is oxidised

Answer 38

the metal

Question 39

when an acid reacts with a metal which species is oxidised

Answer 39

hydrogen

Question 40

what are the four state symbols and what do they stand for

Answer 40

(s) solid, (l) liquid, (g) gas, (aq) aqueous or dissolved in water

Question 41

what is the formula for sulfate

Answer 41

SO4 2-

Question 42

What is the formula for nitrate

Answer 42

NO3

Question 43

what is the formula for carbonate

Answer 43

CO3 2-

Question 44

what is the formula for hydrochloric

Answer 44

HCl