Q3 of 10 Page 46

A student has a piece of copper sulphate (CuSO4) crystal. Explain the method of calculating the number of CuSO4 molecules in that crystal. (Given atomic masses: Calcium =40, Sulphur = 32 and Oxygen=16)

First, we calculate the molar mass of copper sulphate (CuSO4) crystal.


Molar mass of CuSO4 = 63 + 32 + 4×16


= 159 g


Now we will calculate the number of moles of copper sulphate (CuSO4)


Number of moles of CuSO4 =


And we know that 1 mole of CuSO4 = 6.023×1023 molecules


Hence, Number of = Number of moles of CuSO4×6.023×1023


molecules of CuSO4


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