Acids, Alkalis & Salts Acids, Alkalis & Salts

GCSE REVISIONGCSE REVISION

1. Name three indictors1. Name three indictors

Methyl OrangeMethyl Orange PhenolphthaleinPhenolphthalein Universal IndictorUniversal Indictor LitmusLitmus

(any three)(any three)

2. Explain why Universal indicator 2. Explain why Universal indicator is the best indicator.is the best indicator.

Because it gives an indication of strong Because it gives an indication of strong and weak in addition to whether a and weak in addition to whether a substance is an acid, an alkali or neutral.substance is an acid, an alkali or neutral.

3. Give the colours and pH scale 3. Give the colours and pH scale for universal indicator.for universal indicator.

1-2: Red1-2: Red 3-4: Orange3-4: Orange 5-6: Yellow5-6: Yellow 7: Green7: Green 8-10:Blue8-10:Blue 11-12: Indigo11-12: Indigo 13-14: Violet13-14: Violet

4.What are the products of a 4.What are the products of a neutralisation reaction?neutralisation reaction?

Salt and waterSalt and water

5. Write a word/balanced chemical 5. Write a word/balanced chemical equation for the reaction between sodium equation for the reaction between sodium

hydroxide and hydrochloric acidhydroxide and hydrochloric acid

Sodium hydroxide + Hydrochloric Acid Sodium hydroxide + Hydrochloric Acid Sodium Chloride + water Sodium Chloride + water

NaOH + HClNaOH + HCl NaCl + HNaCl + H22OO

6. 6. Write a word/balanced chemical equation Write a word/balanced chemical equation for the reaction between aluminium oxide and for the reaction between aluminium oxide and

sulphuric acidsulphuric acid

Aluminium oxide + Sulphuric Acid Aluminium oxide + Sulphuric Acid Aluminium sulphate + waterAluminium sulphate + water

AlAl22OO33+ 3H+ 3H22SOSO44 AlAl22(SO(SO44))33+ 3H+ 3H22OO

77. . a. Draw the apparatus you would use to collect the gas a. Draw the apparatus you would use to collect the gas when zinc reacts with sulphuric acid.when zinc reacts with sulphuric acid.b. Name the gas produced and give the testb. Name the gas produced and give the test

b. Hydrogen gas. b. Hydrogen gas. A lit splint goes out A lit splint goes out

with a squeaky pop.with a squeaky pop.

a.

8.8. Explain how you would prepare copper sulphate in a lab Explain how you would prepare copper sulphate in a lab

using copper carbonate and sulphuric acid.using copper carbonate and sulphuric acid.

9. a)Explain why you cannot use filtration-evaporation to prepare 9. a)Explain why you cannot use filtration-evaporation to prepare

sodium chloride insodium chloride in a lab.a lab.

b) Give an alternative method that you could useb) Give an alternative method that you could use

a) Sodium carbonate a) Sodium carbonate is not insoluble. is not insoluble. Therefore you cannot Therefore you cannot filter off the excess filter off the excess before evaporation.before evaporation.

b) Titration using b) Titration using sodium hydroxide and sodium hydroxide and hydrochloric acid.hydrochloric acid.

10. Name the reaction that is used 10. Name the reaction that is used to prepare insoluble salts.to prepare insoluble salts.

PrecipitationPrecipitation

The following questions The following questions are are HigherHigher Tier Tier onlyonly

11.11.a) What is meant by a strong acid?a) What is meant by a strong acid?

b) Give an exampleb) Give an example

a) One which dissociates (breaks up) fully a) One which dissociates (breaks up) fully into ions when aqueousinto ions when aqueous

b) HCl b) HCl (aq) (aq) HH22SOSO44 (aq)(aq)

12. Why is the pH of weak acids higher than that of the 12. Why is the pH of weak acids higher than that of the same volume of strong acids?same volume of strong acids?

Because weak acids do not dissociate fully Because weak acids do not dissociate fully when aqueous. when aqueous.

This means that there are less H+ ions This means that there are less H+ ions present in the solution, leading to a higher present in the solution, leading to a higher pH.pH.