SC8 - Acids and Alkalis

Question 1

What is an acidic solution?

Question 2

what is an alkali solution?

Question 3

What is the pH scale?

Question 4

What are the acid-alkali indicators?

Question 5

What are the corresponding colours for each indicator in acids, alkalis and neutral solutions?

Answer 5

Indicator - Acidic - Neutral - Alkaline
Litmus paper - Red - Purple - Blue
Methyl orange - Red - Yellow - Yellow
Phenolphthalein - Colourless - Colourless - Pink

Question 6

Describe the limitations of methyl orange when determining if a solution is alkaline.

Question 7

Describe the limitations of phenolphthalein when determining if a solution is acidic.

Question 8

What is produced in excess when acids are dissolved in water? Give an example of this happening,

Question 9

What is produced in excess when alkalis are put in water? Give an example.

Question 10

How does the concentration of hydrogen/hydroxide ions affect acidity?

Question 11

Exam Q -
Explain why the pH of a hcl acid increases when pure water is added. (2 marks)
What would happen to the pH of a salt solution ( pH 7) if pure water was added ? (2 marks)

Question 12

What is the equation for concentration using volume and amount dissolved?

Answer 12

concentration = amount dissolved / volume

Question 13

How does a change in pH affect the concentration of hydrogen ions in an acid?

Question 14

What is dissociation in acids, give the 2 types and how does each one affect the strength of the acid?

Question 15

What are bases and what do they form?

Question 16

What is the equation of neutralisation reaction?

Question 17

What happens during neutralisation?

Question 18

What is the method of preparing soluble salts for example when you obtain tin chloride from hydrochloric acid and tin oxide?

Question 19

Magnesium nitrate can be made by reacting magnesium oxide with an acid.
a. Which acid?
b. Why should the acid solution be warmed slightly?
c. Why is the magnesium oxide added in excess?
d. Why is the mixture filtered?
e. Why is the salt solution heated?

Question 20

Describe the practical for preparing copper sulfate.

Question 21

What is a base which can dissolve in water?

Question 22

Give 2 examples of soluble bases.

Question 23

When alkali bases react with acids to produce salt and water, what is the equation?

Question 24

Describe the core practical for investigating neutralisation.

Question 25

How do you obtain soluble slats from alkalis?

Question 26

What is titration?

Question 27

What is seen as hydrogen gas bubbles are produced when metals and acids react?

Question 28

What is the equation for metals and acids reacting?

Question 29

Hydrogen is collected in a test tube during the reaction between magnesium and hydrochloric acid. Describe the laboratory test for hydrogen.

Answer 29

Put a lighted splint near the mouth of the test tube. Hydrogen ignites with a squeaky pop.

Question 30

What is the equation for when acids react with carbonates?

Question 31

Carbon dioxide is given off during the reaction between copper carbonate and hydrochloric acid. Describe the laboratory test for carbon dioxide.

Answer 31

Bubble the gas through limewater Carbon dioxide turns limewater milky or cloudy white.

Question 32

Key fact:

Answer 32

Metal oxides and metal hydroxides both react with acids to produce salts and water.

Question 33

Explain why gold sulfate isn't formed when gold is added to dilute sulfuric acid.

Question 34

What are spectator ions?

Question 35

Chloride and nitrate ions are spectator ions. The ionic equation is: 2H⁺ + CO3²⁻ → H20 + CO2 Write the ionic equation for the reaction between magnesium carbonate and hydrochloric acid.

Question 36

What is oxidisation?

Question 37

What is reduction?

Question 38

What does OIL RIG stand for?

Question 39

What is the test for CO2?

Question 40

Exam Q - Describe a test to show a gas is hydrogen. (2 Marks)

Question 41

What is precipitation?

Question 42

What substances are insoluble?

Question 43

What substances are soluble?

Question 44

Write the equation for the CO2 test.

Question 45

Describe a method to prepare insoluble salts.