THE BRIGADE SCHOOL
CHEMISTRY - VIII (Revision worksheet)
CH- 1) LANGUAGE OF CHEMISTRY
2) CHEMICAL REACTIONS
I
Fill in the blanks1. Catalyst used in preparation of ammonia gas ______________.
2. Sodium nitrate on thermal decomposition gives _______________________.
3. Substances formed as a result of the reaction is called ______________.
4. Reversible reactions are represented by the symbol ________.
5. Reaction between two substances to give two products by interchanging of radicals is termed
as ____________________________________________.
6. Representation of elements by figurative symbols was given by__________.
7. The chemical reaction in which the products formed react together again form the original
reactants (under particular conditions) is called __________________.
8. Chemical change in which matter changes into a new substance or substances___________.
9. Phosphorus pentoxide dissolves in water to form ___________.
10. The valency of the noble gas_________.
II.
2.
3.
4.
5.
6.
7.
8.
9.
Give the scientific term forReaction in which an element placed higher in the activity series displaces the element
placed below it from a solution of its compound.
Reaction in which two or more elements or compounds combine to give one compound.
Group of atoms of different elements behaving as a single unit.
A compound alter the rate of reaction but does not take part in it.
Combining power of the element with another element to form compound.
Elements arranged in their increasing order of their atomic number in a table.
It denotes the no of atoms of each element in a compound.
Chemical reaction which proceeds with absorption of heat energy.
Reaction in which a chemical compound decomposes into two or more simple substances.
1.
2.
3.
Correct the false statement by changing the underlined word:
Silver salts undergo combination reactions.
The colour of mercuric oxide is silvery white.
Mg reacts with dil sulphuric acid to liberate sulphur dioxide gas.
1.
3.
5.
Give the symbol of the following radicalsZincate
2. Permanganate
Dichromate
4.Plumbite
Aluminate
6.bisulphate
1.
III
IV
V
Idertify the type of reactions1.
2.
3.
4.
5.
6.
VI
CaCO3
CaO + CO2
2HCl → H2 +Cl2
2KClO3 → 2KCl + 3O2
PbO2 + SO2→ PbSO4
NH4NO3 →N2O + 2H2O
NH4NO3 + NaCl→ NaNO3+NH4Cl
Give reason-
1.
2.
3.
4.
5.
6.
Mercury can form two types of chlorides.
Copper can exist as Cu+ and Cu2+
Hg and Ag rarely form hydroxide.
Formation of ammonia is a reversible reaction.
Silver salts are generally kept in dark coloured bottles.
An equation should be balanced.
1.
3.
5.
State the formula ( step by step) of following compoundsPotassium carbonate 2. Sodium sulphite
Calcium nitrate
4. Ammonium carbonate
Sodium bicarbonate 6. Carbonic acid
VII
VIII 1.
2.
ii)
Give the information and limitation provided by a chemical equation. ( any 2)
For the given general equation AB + CD → AD +CB
Identify the type of reaction and jusytify why formula of one of the product must be written
as CB , not BC.
Define the given equation with an example.
3.
a)
b)
For given general equation- A + BC → AC + B
Identify the type of reaction.
Explain with the help of an equation.
4.
5.
Define variable valency. Write the variable valencies of iron.
Iron reacts with steam to form triferrictetroxide. Give the balanced equation for this
reversible reaction.
Define the following terms with examplea)Thermal dissociation b) electrolytic decomposition c) photochemical decomposition
i)
6.
7.
8.
9.
Define positive, negative catalyst, promoter and enzymes with example.
Differentiate between following with examplea) Exothermic reaction and endothermic reaction
b) Thermal decomposition and thermal dissociation
Give two examples each of following oxidesa) Acidic oxide b) basic oxide c) amphoteric oxide d) neutral oxide e) peroxide
IX
A
Answer the question based on the diagram given-
i)
ii)
A
B
Observe the type of reaction shown in diagram A and B and answer the questionIdentify the type of reaction shown in the diagram A and B.
Give one major difference between both the reaction.
B
i)
ii)
Identify the type of reaction and define the same.
Write a balanced equation for the reaction and identify the precipitate formed.
1.
2.
3.
4.
5.
6.
Complete and balance the following equationsPbO2 + HCl →
ZnO + NaOH →
Pb( NO3)2 →
FeCl3 + NH4OH →
ZnO + NaOH →
Al + H2SO4 →
X