Q3 of 20 Page 143

Answer the following:

Write the advantages of writing a chemical equation using formulae and symbols.

The advantages of writing a chemical equation using formulae and symbols:


For example: C + O2→ CO2


The equation using symbols


i) This method helps us in knowing the reactants and products only.


ii) This method also helps us in knowing the correct relation between the quantities of reactants consumed and products formed C:O2: CO2 = 1:1:1


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3

Answer the following:

Mention one example each for the different types of chemical reactions.

 3

Answer the following:

Classify the following into chemical combination, decomposition, displacement and double displacement reaction.


a) CaCO3 CaO + CO2↑


b) 2AgNO3 + Cu → Cu(NO3)2 + 2Ag ↓


c) 2SO2 + O2→ 2SO3↑


d) NaCl + AgNO3→ AgCl ↓ +NaNO3

3

Answer the following:

During winter many plant leaves fallen on the earth do not cause pollution. But plastic papers which are thrown on the earth cause pollution. Name the types of chemical reaction associated with this observation.

 3

Answer the following:

L.P.G. gas contains butane. Its molecular formula is C4H10. Name the possible products obtained by its complete combustion.