Question

203. 1.2g of Mg (At. mass 24) will produce MgO
equal to
1) 0.05 gm 2) 2g 3) 40 mg 4) 4g.
of

Answer 1

Answer:

Thus on Reaction of 1 mole of CaCO

3

& 1 mole of MgCO

3

, the residue left is 14 mole of CaO & 1 mole of MgO

Molecular wt of CaCO

3

=100 g MW of MgCO

3

=84 g

M wt of CaO=56 gMW of MgO=40 g

Thus when a mixture of 184 g is heated, residue weight 96 g

Also, when a mixture of 92 g is heated, residue weight 48 g

A mixture of contains 84 g MgCO

3

∴ A mixture of 92 g contains 42 g MgCO

3

Answer 2

1 mole of Mg will give 1 mole of MgO

now 1.2 g of mg is 1.2 / 24 = 0.05 moles

So 0.05 moles of MgO will be produced

so will be 0.05 x(24+ 16)

= 2 g