1.

A sample of hydrated copper sulphate is heated to drive off the water of crystallization, cooled and reweighed 0.869 g of CuSO_(4)aH_(2)O gave a residue of 0.556 g. Find the molecular formula of hydrated copper sulphate.

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :0.869 g of `CuSO_(4)*aH_(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)O` gave a residue of 0.556 g of Anhydrous `CuSO_(4)` `:` Weight of a `H_(2)O` molecule = 0.869-0.556 = 0.313 g<br/>Molecular weight of `H_(2)O = (1xx2)+16=2+16=18`<br/>No. of moles of water =`("Mass")/("Molecular mass")`<br/>`CuSO_(4)*5H_(2)O` - Molecular mass = 63.5 + <a href="https://interviewquestions.tuteehub.com/tag/32-307188" style="font-weight:bold;" target="_blank" title="Click to know more about 32">32</a> + 64 + <a href="https://interviewquestions.tuteehub.com/tag/90-341351" style="font-weight:bold;" target="_blank" title="Click to know more about 90">90</a> = 249.5 g<br/>249.5 gof `CuSO_(4) .5H_(2)O` on heating gives 159.5 g of `CuSO_(4)`<br/>. 0.869 g of `CuSO_(4)*aH_(2)O` on heating gives<br/>`159.5/249.5 xx 0.869`<br/>= 0.556 g of anhydrous `CuSO_(4)`<br/>`:.` a =5<br/>The molecular formula of hydrated copper <a href="https://interviewquestions.tuteehub.com/tag/sulphate-1234306" style="font-weight:bold;" target="_blank" title="Click to know more about SULPHATE">SULPHATE</a> = `CuSO_(4)*5H_(2)O.`</body></html>


Discussion

No Comment Found

Related InterviewSolutions