C4 Chemical Changes

Question 1

What is reactivity?

Answer 1

How chemically reactive a metal is. When added to water some metals have high reactivity and react very vigorously and other metal barely react because they have low reactivity

Question 2

What is the reactivity series?

Answer 2

Places metals in order of reactivity

Question 3

What is the order of reactivity?

Answer 3

Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold

Question 4

How do potassium, sodium, lithium and calcium react with water?

Answer 4

Fizzes, give off hydrogen gas

Question 5

How do magnesium, aluminium, zinc and iron react with water?

Answer 5

Reacts very slowly

Question 6

How do lead, tin, copper, silver, gold react with water?

Answer 6

No reaction

Question 7

How do potassium, sodium and lithium re at with acid?

Answer 7

Explodes

Question 8

How do calcium, magnesium, aluminium, zinc and iron react with acid?

Answer 8

Fizzes, gives of hydrogen gas.

Question 9

How do tin and lead react with acid?

Answer 9

Reacts slowly with WARM acid

Question 10

How do copper, silver and gold react with acid?

Answer 10

No reaction

Question 11

Which metals can be extracted via electrolysis?

Answer 11

Potassium, sodium, lithium, calcium, magnesium, aluminium

Question 12

Which metals can be extracted by reduction with carbon?

Answer 12

Zinc, iron, tin, lead

Question 13

Which metals can be extracted by mining from the Earth’s crust?

Answer 13

Copper, silver, gold

Question 14

What is oxidation in terms of oxygen?

Answer 14

Gains oxygen in a reaction

Question 15

What is reduction in terms of oxygen?

Answer 15

Loses oxygen in a reaction.

Question 16

What is a displacement reaction?

Answer 16

A more reactive element takes the place of a less reactive element

Question 17

What does a metal’s reactivity depend on?

Answer 17

How readily it forms an ion by losing electrons

Question 18

What are steps for writing an ionic equation?

Answer 18

Check symbol equation is balanced
Identify all aqueous ionic compounds
Write those compounds out as ions
Remove spectator ions

Question 19

What is a half equation?

Answer 19

Shows half of the ionic equation in terms of electrons

Question 20

What is oxidation in terms of electrons?

Answer 20

The loss of electrons

Question 21

What is reduction in terms of electrons?

Answer 21

The gain of electrons

Question 22

What substance releases H+ ions?

Answer 22

Acids are compounds that, when dissolved in water, release H+ ions

Question 23

What are the three main acids?

Answer 23

Sulfúrico acid, Nitric acid, Hydrochloric acid

Question 24

What is the symbol for sulfuric acid?

Answer 24

H2SO4

Question 25

What is the symbol, for nitric acid?

Answer 25

HNO3

Question 26

What is the symbol for hydrochloric acid?

Answer 26

HCl

Question 27

What substance release OH-?

Answer 27

Alkalis are compounds that, when dissolved in water, release OH- ions

Question 28

What is the pH scale?

Answer 28

A measure of acidity and alkalinity which runs from 0 to 14

Question 29

Which solutions are acidic?

Answer 29

<7

Question 30

Which solutions are alkaline?

Answer 30

>7

Question 31

Which solutions are neutral?

Answer 31

7

Question 32

What is a logarithmic scale?

Answer 32

As the pH scale increases by 1 the number of H+ ions decreases by 10x and the number of OH- ions increases by 10x

Question 33

What is universal indicator?

Answer 33

Can tell us the approximate pH of a solution

Question 34

What is an electronic pH probe?

Answer 34

Tell us the exact pH of a solution

Question 35

What is a strong acid?

Answer 35

When dissolved in water, every molecule splits up into ions - they are completely ionised e.g sulfuric, nitric, hydrochloric

Question 36

What is a weak acid?

Answer 36

Only a percentage of their molecules split up into ions when dissolved in water - they are only partially ionised e.g ethanoic, citric, carbonic

Question 37

What is concentration?

Answer 37

How much of a substance there is dissolved in water

Question 38

What is a concentrated acid?

Answer 38

Lots of acid in small volumes of water

Question 39

What is a less concentrated acid?

Answer 39

Little acid in a large volume of water

Question 40

How are salts formed?

Answer 40

When acids react with metals or metal compounds, they form salts

Question 41

What salt does hydrochloric acid produce?

Answer 41

Chloride salt

Question 42

What salt does nitric acid produce?

Answer 42

Nitrate salt

Question 43

What salt does sulfuric acid produce?

Answer 43

Sulfate salt

Question 44

What does a reaction of acid with a metal produce?

Answer 44

Metal Salt + hydrogen

Question 45

What does a reaction of acid with a metal hydroxide produce?

Answer 45

Metal salt + water

Question 46

What does a reaction of acid with a metal oxide produce?

Answer 46

Metal salt + water

Question 47

What does a reaction of acid with metal carbonate produce?

Answer 47

Metal salt + water + carbon dioxide

Question 48

What type of reaction is the reaction of acids with metals?

Answer 48

Redox

Question 49

What is neutralisation?

Answer 49

Bases neutralise acids to form water in neutralisation reactions. Some metal hydroxides dissolve in water to form alkaline solutions called alkalis. Some metals and metal hydroxide do not dissolve in water. They are bases but are not alkalis.

Question 50

What is crystallisation?

Answer 50

Chose the correct acid and base to produce the salt Put some of the dilute acid into a flask. Heat gently with a Bunsen burner Add a small amount of the base and stir Keep adding the base until no more reacts and it is in excess Filter to remove unreacted base Add the remaining solution to an evaporating dish Use a water bath to evaporate the water. Salt crystals will be left behind

Question 51

What does redox stand for?

Answer 51

Reduction and oxidation

Question 52

What is a spectator ion?

Answer 52

An ion that does not change charge

Question 53

What is the method for making soluble salts?

Answer 53

Measure out 10cm^3 acid Add acid to boiling tube in hot water bath Add base to acid until powder remains after stirring (excess) Filter the solution Use an evaporating basin to evaporate the solution Pat crystals dry