test on Making Salt Methods & Acid Reactions

Question 1

when is a salt formed?

Answer 1

neutralisation reaction

Question 2

general equation for neutralisation reaction

Answer 2

acid + base —-> salt + water

Question 3

titration (6 marks)

Answer 3

• using pipette +c pipette filler add 25cm^3 alkali to a conical flask with 2/3 drops of indicator
• fill burette with acid at below eye level
• using burette add acid to alkali slowly giving conical flask a regular swirl. Go especially slowly when colour change is about to be reached
• indicator changes colour when all the alkali has been neutralised
• record volume of acid used to neutralise alkali and repeat process for accurate results

Question 4

what does a titration experiment allow you to find?

Answer 4

exactly how much acid is needed to neutralise a quantity of alkali

Question 5

making soluble salts practical (6 marks)

Answer 5

• heat acid in water bath in fume cupboard to avoid releasing acid fumes into room
• add base to acid which will react to produce soluble salt + water.
• filter off excess solid to get a solution containing only salt and water
• heat solution gently using bunsen burner to slowly evaporate off some water.
• leave solution to cool and allow salt to crystallise
• filter off solid salt and leave to dry

Question 6

common salts of sodium potassium and ammonium

Answer 6

soluble

Question 7

nitrates

Answer 7

soluble

Question 8

common chlorides

Answer 8

soluble (except silver chloride + lead chloride)

Question 9

common sulfates

Answer 9

soluble (except lead, barium and calcium sulfate

Question 10

common carbonates

Answer 10

insoluble (except for sodium potassium and ammonium)

Question 11

common hydroxides

Answer 11

insoluble (except for sodium potassium and calcium)

Question 12

making lead sulfate (precipitation reaction) (8)

Answer 12

• add 1 spatula of lead nitrate to test tube and add water to dissolve
• shake throughly to ensure all has dissolved. in a separate test tube, do the same with 1 spatula of magnesium sulfate
• tip 2 solutions into a small beaker and give it good stir to make sure its all mixed together. Lead sulfate should precipitate out.
• put folded piece of filter paper into filter funnel and stick to funnel into a conical flask.
• pour contents of beaker in middler of filter paper and make sure solution doesn’t go above filter paper
• swill out beaker with more deionised water and tip into filter paper to make sure you get all the precipitate from the beaker
• rinse contents of filter paper with deionised water to make sure all soluble magnesium nitrate has been washed away
• scrape leads sulfate onto fresh filter paper and leave to dry in oven