3.1 Acids

Question 1

What does oxidising mean?

Answer 1

Provides oxygen which allows materials to burn more fiercely

Question 2

What does toxic mean?

Answer 2

Can cause death by being swallowed, inhaled or absorbed through the skin

Question 3

What does highly flammable mean?

Answer 3

Catches fire easily

Question 4

What does an environmental hazard mean?

Answer 4

Harmful to organisms and to the environment

Question 5

What does harmful mean?

Answer 5

Can cause irritation, reddening or blistering of the skin

Question 6

What does corrosive mean?

Answer 6

Destroys material , including living tissues

Question 7

Safety precautions for acids

Answer 7

Wear eye goggles, dilute the acid with water

Question 8

Acid

Answer 8

A substance with a pH less than 7

Question 9

What will acids dissociate into in water

Answer 9

H+ ions

Question 10

What will alkalis dissociate into in water

Answer 10

OH- ions

Question 11

Base

Answer 11

A substance that neutralises an acid

Question 12

Alkali

Answer 12

A soluble base

Question 13

What colour is pH 1 on the universal indicator

Answer 13

Red

Question 14

What colour is pH 14 on the universal indicator

Answer 14

Purple

Question 15

What colour is pH 7 on the universal indicator

Answer 15

Green

Question 16

What colour is litmus in acid

Answer 16

Red

Question 17

What colour is litmus in neutral

Answer 17

Purple

Question 18

What colour is litmus in alkali

Answer 18

Blue

Question 19

What colour is methyl orange in acid

Answer 19

Red

Question 20

What colour is methyl orange in neutral

Answer 20

Yellow

Question 21

What colour is methyl orange in alkali

Answer 21

Yellow

Question 22

What colour is phenolphthalein in acid

Answer 22

Colourless

Question 23

What colour is phenolphthalein in neutral

Answer 23

Colourless

Question 24

What colour is phenolphthalein in alkali

Answer 24

Pink

Question 25

Neutralisation equation

Answer 25

Acid + base -> salt + water

Question 26

What does pH measure?

Answer 26

The concentration of H+ or OH- ions

Question 27

What will happen to an acid in water

Answer 27

It will dissociate and lose its H+ ion

Question 28

Strong acid

Answer 28

Will fully dissociate in water

Question 29

Weak acid

Answer 29

Will partially dissociate in water

Question 30

How much will the concentration of acid increase by if the pH decreases by 1

Answer 30

A factor of 10

Question 31

Which salt ending will products of hydrochloric acid have

Answer 31

Chloride

Question 32

Which salt ending will products of nitric acid have

Answer 32

Nitrate

Question 33

Which salt ending will products of sulfuric acid have

Answer 33

Sulfate

Question 34

Which salt ending will products of phosphoric acid have

Answer 34

Phosphate

Question 35

What is the equation for reacting an acid with a metal

Answer 35

Acid + metal -> salt + hydrogen

Question 36

What is the test for hydrogen

Answer 36

Will make a squeaky pop with a little splint

Question 37

What is the equation for reacting an acid with a metal carbonate

Answer 37

Acid + metal carbonate -> salt + water + carbon dioxide

Question 38

Test for carbon dioxide

Answer 38

Bubble the gas through limewater and see if it goes cloudy

Question 39

What will a graph look like if the x axis is the amount of base added and the y axis is the pH

Answer 39

There will be a small slope upwards until a rapid jump where the acid is neutralised

Question 40

Hydrochloric acid

Answer 40

HCl

Question 41

Sulfuric Acid

Answer 41

H2SO4

Question 42

Nitric Acid

Answer 42

HNO3

Question 43

Common soluble salt compounds

Answer 43

Salts of sodium, potassium and ammonium

Question 44

Which nitrates are soluble

Answer 44

All of them

Question 45

Which nitrates are insoluble

Answer 45

None of them

Question 46

Which chlorides are insoluble

Answer 46

Silver chloride and lead chloride

Question 47

Which chlorides are soluble

Answer 47

Most of them

Question 48

Which sulfates are insoluble

Answer 48

Lead sulfate, barium sulfate and calcium sulfate

Question 49

Which sulfates are soluble

Answer 49

Most of them

Question 50

Which carbonates and hydroxides are soluble

Answer 50

Sodium, potassium and ammonium

Question 51

Which carbonates and hydroxides are insoluble

Answer 51

Most of them

Question 52

How to make insoluble salts from two soluble salts

Answer 52

1. Add the two soluble salts into separate tests tubes of deionised water 2. Tip the two solutions into a beaker (the insoluble salt should precipitate out) 3. Filter into a conical flask 4. Rinse the contents of the filter paper with deionised water 5. Leave the insoluble salt to dry

Question 53

Why is deionised water added to the making insoluble salts experiment

Answer 53

So that there are no other ions about

Question 54

Improvements to the making insoluble salts experiment

Answer 54

Use deionised water, stir the beaker when the solutions are added, swill put the beaker with deionised water during filtration

Question 55

How to make a soluble salt from an acid and an insoluble base

Answer 55

1. Heat the acid in a water bath 2. Add base until the base is in excess 3. Filter off the excess solid 4. Heat the solution using a Bunsen burner 5. Leave the solution to cool and crystallise

Question 56

Why is the solution heated at the start in the making soluble salts with an acid and insoluble base experiment

Answer 56

To speed up the reaction between the acid and base

Question 57

What does the solution contain after being filtered in the making soluble salts with an acid and insoluble base experiment?

Answer 57

Salt and water

Question 58

When does neutralisation occur in the making soluble salts with an acid and insoluble base experiment

Answer 58

When the base is in excess

Question 59

Why is the salt and water heated near the end in the making soluble salts with an acid and insoluble base

Answer 59

So that the water evaporates

Question 60

How to make a soluble salt from an acid and an alkali

Answer 60

1. Measure a recorded amount of acid into a conical flask 2. Add a few drops of indicator 3. Slowly add alkali using a burette until the indicator changes colour 4. Record the volume of alkali it took to neutralise 5. Repeat the experiment with the same volumes but no indicator 6. Heat up the solution 7. Leave it to crystallise

Question 61

Why shouldn't universal indicator be used in the making soluble salts from an acid and alkali experiment

Answer 61

The change in colour is too gradual

Question 62

Why can't you add excess alkali to the solution in the making soluble salts from an acid and alkali experiment

Answer 62

The solution will be contaminated with the excess alkali

Question 63

At what point is the solution neutralised in the making soluble salts from an acid and alkali experiment

Answer 63

As soon as the indicator changes colour

Question 64

Why is the experiment repeated without the indicator in the making soluble salts from an acid and alkali experiment

Answer 64

The indicator won't contaminate the solution

Question 65

Why is the solution heated at the end of the making soluble salts from an acid and alkali experiment

Answer 65

To evaporate the water