21.

Write a balanced equation for the reaction of the dilute hydrochloric acid with each of the following :

Sodium sulphite

Write a balanced equation for the reaction of the dilute hydrochloric acid with each of the following :

Sodium thiosulphate solution

Of the two gases, ammonia and hydrogen chloride, which is denser?  Name the method of collection of this gas.

Give one example of a reaction between the above two gases which produces a solid compound

Write a balanced equation for a reaction in which ammonia is oxidised by:

A metal oxide

Write a balanced equation for a reaction in which ammonia is oxidised by:

a gas which is not oxygen

The figure below illustrates  the apparatus used in the laboratory preparation of nitric acid,

(i)Name A (a liquid), B (a solid) and C (a liquid),.

(Do not give the formulae)

(ii) Write an equation to show how nitric acid undergoes decomposition

(iii) Write the equation for the reaction in which copper is oxidised by concentrated nitric acid.

A group of the element is the Periodic table are given below. (Boron is the first member of the group and Thallium is the last.)

Boron

Aluminium

Gallium

Indium

Thallium

Answer the following question in relation to the above of element;

i)   Which element has the most metallic character?

ii)  Which element would be expected to have the highest electronegativity? : 

iii) If the electronic configuration of Aluminium is 2,8,3 how many electrons are there in the outer shell of Thallium? 

iv) The atomic number of Boron is 5. Write the chemical formula of the compound formed when Boron react with chlorine. 

v)  Will the elements in the group to the right to this Boron group be more metallic or less metallic in character? Justify your answer

 A compound X consist of 4.8% carbon and 95.2% bromine by mass.

i)  Determine the empirical formula of this compound working correctly to one decimal place(C=12, Br=80)

ii) If the vapour density of the compounds is 252, what is the molecular formula of the compound?

iii) Name the type of chemical reaction by which X can be prepared from ethane

A sample of ammonium nitrate when heated yields 8.96 litres of steam (measured at STP).

NH₄NO₃ ----> N₂O +2H₂O

i) What volume of dinitrogen oxide is produced at the same time as 8.96 litres of steam?

ii) What mass of ammonium nitrate should be heated to produce 8.96 litres of steam?( relative molecular mass of ammonium nitrate is 80()

iii) Determine the percentage of oxygen in ammonium nitrate (O=16).