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Question
Calculate the number of molecules in one Kg of calcium chloride.
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Solution
Molecular mass of CaCl2 = 40 + (35.5 x 2) = 111
111 g of CaCl2 contain molecules= 6.02 x 1023
∴ 1kg = 1000 g of CaCl2 contain molecules
= `602/(111 xx 100) xx 1000 xx 10^23`
= `6020/111 xx 10^23`
= 5.42 x 1024
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