*The Worsheet for formative evaluation

Worksheet Mole Concept:

1. (a) Define the term mole

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(b) Complete the table below:

Mass /g Number of moles Number of particles 13 g zinc

0.05 moles hydrogen atoms 4.2 x 1022 molecules of O2

7.2 x 1024 atoms of copper

1.25 moles of CaCO3

1.07 kg of NH4Cl

2. (a) Calculate the mass of residue left when 10 g CaCO3 is completely decomposed by heat.

(b) Calculate the mass of NH4Cl formed when 3.4 g of NH3 is reacted with excess HCl.

(c) What mass of SO2 will be required to produce 10 tonnes of Sulphuric acid?

2SO2 + O2 + 2H2O  2H2SO4

(d) Calculate the mass of FeS formed when 8 gram Fe is reacted with 8 gram S.

3. (a) Barium nitrate when heated decompose into the oxide, nitrogen dioxide and oxygen. (i) Write a balanced equation for the reaction.

(ii) When 26.1 gram of impure barium nitrate was heated 12.0 gram of the oxide was collected. Calculate the percentage impurity.

(iii) What mass of the impure Ba(NO3)2 must be heated to produce15.4 gram of BaO?

(b) Use the mole concept to calculate the approximate average mass of 1 atom of hygrogen.