Perception Of Salts

Question 1

Explain why it is important that magnesium is in excess

Answer 1

To neutrilese all nitric acid so solution only contain magnisium nitrate

Question 2

Explain titration

Answer 2

1.mesure 25 cm3 of naoH solution with pippette and transfer solution to conical flask
2.add 3 drops of phenolphathline
3.add dilute sulphuric acid in burrette and measure initial volume
3.add the acid drop by drop to the alkali in the flask and swirl until colour change
4.mesure final volume of acid used and repeat to obtain concordant result

Question 3

Describe how the student can obtain dry crystals of hydrated magnesium nitrate from the mixture at end of reaction (dissolving)

Answer 3

1.add excess solid a little at a time in a beaker half filled with sulphuric acid during stiring
2.filter mixture to remove excess solid
3.heat the filtration and evaporate till Crystillastion pint in evaporating basin
4.leave solution to cool and crystallises when crystals formed on glass Rod
5.seprate by filtration and dry between 2 filter paper

Question 4

Appaurtas use to add naoh solution

Answer 4

Pippette

Question 5

Why is is better to use phenolphthalien indicator rather than universal indicator in titration

Answer 5

Has only one colour and give sharp end point

Question 6

Why we warm acid

Answer 6

To increase Rate of reaction

Question 7

How will student know when the copper (Ii) oxide is in excess

Answer 7

When solid perciptae formed

Question 8

How will student know when the crystallisation point reached

Answer 8

When crystals formed on glass rod

Question 9

Precipitation

Answer 9

1.mix 2 solutions,preciptate of nacl2(ex) formed and stir them with glass Rod
2.filter the mixture
3.wash residue by distilled water to remove any soluble substances
4.dry residue between 2 filter paper r drying oven

Question 10

Colour of perciptate silver chloride

Answer 10

White

Question 11

Explain why it is important that magnesium is in excess

Answer 11

To neutrlise all nitric acid so solution only contain magnesium nitrate

Question 12

State why the student uses an excess of zinc powder

Answer 12

To neutrilise all acid

Question 13

Give the reason for using the white tile

Answer 13

To see the colour change clearly at the end poiny

Question 14

Colour change of methyl benzene in acid natural alkali

Answer 14

Red(acid)
Orange(neutral)
Yellow(alkali)

Question 15

State why we filter mixture in dissolving

Answer 15

To remove excess solid

Question 16

Why is it better to use distilled water rather than tap water to wash the solid residue

Answer 16

No soluble ions

Question 17

Why leaving solid in warm place is important

Answer 17

To evaporated water to dry it