Question

If a sample of CuSo4. 5H2O contains 64g S, calculate mass of H present in sample

Answer 1

Answere:

20g

Explanation:

mass of s = 32

now no. of moles = given mass / molar mass

                              = 64/32

                              = 2 moles

therefore ;mass of h will be = 2×5×2    

                                       Ans = 20                                

Answer 2

Concept:

The number of moles of any element or molecule can be defined as

Number of moles, n = Given Mass/ Molecular Mass

Given:

64g of S in CuSO₄.5H₂O

Find:

The Mass of H which is present in the sample.

Solution:

The total molar mass of CuSO₄.5H₂O = 1 Cu + 1 S + 4 O + 10 H + 5 O

= 63.5 + 32 + (4×16) + (10×1) + (5×16) = 249.5 g

Given, that the mass of Sulphur is 64 g.

In one mole, the mass of Sulphur is 32 g.

So, the number of moles, n = 64/32 = 2 moles.

As 2 moles of the CuSO₄.5H₂O is present. One mole contains 10 grams of hydrogen.

2 moles of the CuSO₄.5H₂O contains 20 grams of hydrogen.

Hence, a total of 20 grams of Hydrogen is present in the sample.

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