Topic 4 Acids (Higher)

Question 1

What are the particles that acids contain?

Answer 1

Hydrogen ions (H+)

Question 2

What are the particles that alkalis contain?

Answer 2

Hydroxide ions (OH-)

Question 3

What is the ionic equation for the reaction between an acid and an alkali?

Answer 3

H+ + OH- –> H₂O

Question 4

What is the formula for Hydrochloric acid?

Answer 4

HCl

Question 5

What is the formula for Sulphuric acid?

Answer 5

H₂SO₄

Question 6

What is the formula for Nitric acid?

Answer 6

HNO₃

Question 7

What is the formula for Sodium hydroxide?

Answer 7

NaOH

Question 8

What is an indicator?

Answer 8

A chemical with changes colour in acid or alkali

Question 9

What is the colour of Universal indicator in acid, neutral and alkali?

Answer 9

Red, green, purple

Question 10

What is the pH of a concentrated acid, neutral and concentrated alkali?

Answer 10

1, 7, 14

Question 11

What is the colour change of phenolphthalein in going from alkali to acid?

Answer 11

Pink to colourless

Question 12

What is the colour change of methy orange in going from alkali to acid?

Answer 12

Yellow to red

Question 13

How does the concentration of an acid effect the pH?

Answer 13

The higher the concentration the lower the pH

Question 14

How does the concentration of an alkali effect the pH?

Answer 14

The higher the concentration the higher the pH

Question 15

Give and equation to calculate the concentration of a solution in g/dm3

Answer 15

concentration = amount of substance (g) / volume (dm³)

Question 16

What is a dm3

Answer 16

1dm³ = 1000cm³ = 1Litre

Question 17

How does the concentration of hydrogen ions effect the pH?

Answer 17

The higher the concentration the lower the pH

Question 18

What happens to the concentration of hydrogen ions if an acid is diluted by a factor of 10?

Answer 18

It decreases by a factor of 10

Question 19

What happens to the pH if an acid is diluted by a factor of 10?

Answer 19

It increases by 1

Question 20

Name 2 ways that you can measure the pH of a solution

Answer 20

Using universal indicator and a chart or using a pH meter

Question 21

What particles do acids contain?

Answer 21

Hydrogen ions (H+)

Question 22

What two ions does hydrochloric acid (HCl) form when it is dissolved in water?

Answer 22

H+ and Cl-

Question 23

Hydrochloric acid (HCl) is a strong acid. What happens when HCl dissolves in water?

Answer 23

All of the HCl dissociates into H+ and Cl- ions

Question 24

What two ions does ethanoic acid (CH₃COOH) form when it is dissolved in water?

Answer 24

H+ and CH₃COO-

Question 25

Ethanoic acid is a (CH₃COOH) is a weak acid. What happens when CH₃COOH dissolves in water?

Answer 25

Only a few of the CH₃COOH molecules dissociate

Question 26

Strong acids fully dissociate. What does dissociate mean?

Answer 26

Splits up into the ions it contains

Question 27

Why is the pH of a weak acid higher than the pH of a strong acid of the same concentration?

Answer 27

The strong acid fully dissociates so produces more hydrogen ions, so has a lower pH

Question 28

What type of compounds are bases ?

Answer 28

Metal oxides and hydroxides

Question 29

Give a general equation for how an acid reacts with a base

Answer 29

Acid + base --\> salt + water

Question 30

What is the name of the type of reaction when a base is added to an acid?

Answer 30

neutralisation

Question 31

What is a salt?

Answer 31

An ionic compound made between a metal and a non-metal

Question 32

What type of salts does hydrochloric acid make?

Answer 32

Chlorides

Question 33

What type of salts does sulphuric acid make?

Answer 33

Sulphates

Question 34

What type of salts does nitric acid make?

Answer 34

Nitrates

Question 35

What are the 4 main state symbols and what do they mean?

Answer 35

(s) solid, (l) liquid, (g) gas, (aq) dissolved in solution

Question 36

Copper oxide is an insoluble base – what does copper oxide look like?

Answer 36

black powder

Question 37

Copper sulphate is a soluble salt – what does CuSO₄ (s) and CuSO₄ (aq) look like?

Answer 37

blue crystals and a blue solution

Question 38

Give the 3 main steps for making a soluble salt from acid and an insoluble base

Answer 38

Add excess base to the acid to neutralise it. Filter off the excess base. Evaporate the filtrate to give the salt

Question 39

Name the acid and the base that could be used to make copper sulphate

Answer 39

copper oxide and sulphuric acid

Question 40

What is an alkali ?

Answer 40

A soluble base

Question 41

Sodium hydroxide is an alkali. What ions are produced when sodium hydroxide is dissolved in water?

Answer 41

Na+ and OH-

Question 42

Sodium hydroxide is an alkali – what does NaOH (aq) look like?

Answer 42

A colourless solution

Question 43

Give the formula and state symbol for the alkali sodium hydroxide

Answer 43

NaOH (aq)

Question 44

Alkalis are bases. Give the general reaction for how an acid reacts with an alkali

Answer 44

Acid + alkali --\> salt + water

Question 45

What type of reaction occurs when an acid reacts with an alkali?

Answer 45

neutralisation

Question 46

What is the ionic equation for the reaction between an acid and an alkali?

Answer 46

H+ + OH- --\> H₂O

Question 47

What is the method called for adding an exact amount of acid to an alkali?

Answer 47

Titration

Question 48

List the main equipment used in a titration

Answer 48

Burette, pipette, conical flask, indicator

Question 49

In a titration what is the point at which the indicator changes colour?

Answer 49

End point

Question 50

What is the colour change of phenolphthalein in going from alkali to acid?

Answer 50

pink to colourless

Question 51

What is the colour change of methy orange in going from alkali to acid?

Answer 51

yellow to red

Question 52

List the main steps for making a soluble salt from an acid and an alkali using titration.

Answer 52

Pipette 25cm³ of alkali into a flask. Add a drop of indicator. Add acid from burette until it changes colour. Record the volume of alkali. Repeat again without indicator. Evaporate the solution to get the salt.

Question 53

Give the general equation for the reaction between an acid and a metal

Answer 53

acid + metal --\> salt + hydrogen

Question 54

What is the name of the type of reaction when an acid reacts with a metal?

Answer 54

neutralisation

Question 55

State two things you would see when a metal such as magnesium reacts with an acid

Answer 55

fizzing and the metal would disappear

Question 56

What is the test for hydrogen gas?

Answer 56

Add a lit splint and get a squeaky pop

Question 57

Why do different metals react differently with acids?

Answer 57

Metals have different reactivity (reactivity series)

Question 58

Why would you not prepare a salt from reaction of a group 1 metal with acid?

Answer 58

It would be too reactive / dangerous

Question 59

Why would you not make copper sulphate from the reaction of copper and sulphuric acid?

Answer 59

Copper is low in the reactivity series and would react very slowly

Question 60

Give the formula and state symbol for Hydrochloric acid?

Answer 60

HCl (aq)

Question 61

Give the formula and state symbol for Sulphuric acid?

Answer 61

H₂SO₄ (aq)

Question 62

Give the formula and state symbol for Nitric acid?

Answer 62

HNO₃ (aq)

Question 63

Give the general equation for the reaction between and acid and a metal carbonate

Answer 63

acid + carbonate --\> salt + carbon dioxide

Question 64

What is the name of the type of reaction when an acid reacts with a metal carbonate?

Answer 64

neutralisation

Question 65

State two thing you would see when a metal carbonate such as calcium carbonate reacts with an acid

Answer 65

the reaction would fizz and the carbonate would disappear

Question 66

What is the test for carbon dioxide gas?

Answer 66

Bubble through lime water and the lime water goes cloudy

Question 67

What is a precipitate?

Answer 67

A solid formed in a solution reaction

Question 68

Name two groups of compounds that are always soluble

Answer 68

All group 1 metal compounds, all nitrates

Question 69

Name two insoluble chlorides

Answer 69

Silver chloride, lead chloride

Question 70

Name two insoluble sulphates

Answer 70

Barium sulphate, lead sulphate, calcium sulphate

Question 71

Which two groups of compounds are mostly insoluble?

Answer 71

Hydroxides and carbonates

Question 72

What is the rule for writing an equation for a precipitation reaction?

Answer 72

The ions from the two solutions reacting swap places

Question 73

What is the state symbol for a precipitate?

Answer 73

(s) solid

Question 74

In a solution precipitation reaction which state symbols would you expect to see in reactants and products?

Answer 74

reactants both would be (aq). Products one would be (aq) and one (s)

Question 75

List the steps to make an insoluble salt from a precipitation reaction

Answer 75

Add the two solutions together in the right quantities, filter off the precipitate, wash with some water, dry in an oven

Question 76

What are the rules for turning a symbol equation into an ionic equation?

Answer 76

Write out the full symbol equation. Split and ionic compounds in solution into the ions they contain. Cancel the spectator ions. Write what is left.

Question 77

In the neutralisation of an insoluble base (e.g. copper oxide) why don’t you split the base into ions?

Answer 77

The ionic compound is not in solution

Question 78

What is the ionic equation for the neutralisation of an alkali?

Answer 78

H+ + OH- --\> H₂O

Question 79

In the ionic equation for the reaction of a metal with acid the metal reacts to form metal ions. Is the metal oxidised or reduced?

Answer 79

oxidised (it loses electrons)

Question 80

In the ionic equation for the reaction of a metal with acid hydrogen ions from the acid form hydrogen gas. Is this oxidation or reduction?

Answer 80

reduction (it gains electrons)

Question 81

What is the ionic equation for a precipitation reaction?

Answer 81

the ions in the precipitate form the precipitate.