5.3 Salts

Question 1

How do we make soluble salts?

Answer 1

By neutralising acids and crystallising the resulting solution

Question 2

What are the two stages of making pure, dry crystals of a soluble salt?

Answer 2

1) Make salt solution
- Using Insoluble base method
- Using the Titration method
2) Crystallise the salt

Question 3

What is the Insoluble Base method?

Answer 3

1) Heat acid (hot acid reacts faster (as more energy))
2) Stir and add base until no more will dissolve (base in excess (all acid used))
3) Filter out excess base

Question 4

Why do we use the Insoluble Base method?

Answer 4

Used when making salts which do not contain sodium, potassium or ammonium

Question 5

What is the acid used in an Insoluble Base method?

Answer 5

Usually HCl, H2SO4 or HNO3

Question 6

What base is used in an Insoluble Base method?

Answer 6

Usually a solid metal oxide

Question 7

Why do we use the titration method?

Answer 7

When making salts which contain sodium, potassium or ammonium

Question 8

What acid is used in the Titration method?

Answer 8

Usually HCl, H2SO4 or HNO3

Question 9

What alkali is used in the Titration method?

Answer 9

Usually NaOH, KOH or NH4OH

Question 10

What is the Titration method?

Answer 10

1) Measure volumes of acid and alkali which neutralise each other
2) Repeat titration but don’t use indicator and use burette to add correct volume to neutralise

Question 11

What is the method of crystallisation?

Answer 11

1) Heat salt solution until crystals start forming (means solution is saturated)
2) All solution to cool (for a few days (lowers solubility))
3) Filter out crystals
4) Dry crystals, by dabbing with filter paper

Question 12

Why do we dab the crystals after filtered?

Answer 12

Removes traces of water

Question 13

What is a precipitate?

Answer 13

An insoluble solid which forms inside a solution

Question 14

How is a precipitate formed?

Answer 14

Ions in the solution collide with each other, a precipitate forms and sinks to the bottom

Question 15

How can you known is an insoluble compounds had been formed?

Answer 15

A precipitate will form

Question 16

How do we make a precipitate?

Answer 16

By mixing solutions

Question 17

What are spectator ions?

Answer 17

Ions that aren’t involved in making a precipitate and remain in the solution as leftovers

Question 18

What type of reaction is used when we just involve the precipitate?

Answer 18

Ionic equation

Question 19

How do we separate the precipitate from the solution?

Answer 19

1) Filter out salt precipitate (keep the residue (salt))
2) Rinse the salt with water (washed traces of solution off) (doesn’t dissolve salt as salt is insoluble)
3) Dry the salt by dabbing with filter paper