Question

Calculate the number of carbon, hydrogen and oxygen atoms in 18 g of glucose.

Answer 1

Molecular formula =$C_6{H}_{12}{O}_6$

Molar mass $=6\times 12+12\times 1+16\times 6=180gmo{l}^{-1}$

Moles in 18g of sample$=\frac{18}{180}=0.1$mole

So,moles of carbon present in sample$=0.1\times 6=0.6$

Moles of hydrogen$=0.1\times 12=1.2$

Moles of oxygen$=6\times 0.1=0.6$

No. of atoms present in carbon$=0.6\times 6.022\times {10}^{23}=3.6\times {10}^{23}$

No. of atoms present in hydrogen$=1.2\times 6.022\times {10}^{23}=7.2\times {10}^{23}$

No. of atoms present in oxygen$=0.6\times 6.022\times {10}^{23}=3.6\times {10}^{23}$