Question

Consider a 1.245 g sample of glucose (C6H12O6)

a. calculate moles of glucose in the sample

b. Moles of carbon in 1 mole glucose

c. moles and mass of carbon in the sample

d. glucose molecule in the sample

Answer 1

(a) Molar mass of glucose = $C_6H_{12}O_6 = 6(12)+12(1)+6(16)= 180 g/mol$

(b) Moles of C in 1 mole of glucose $C_6H_{12}O_6=6$ moles

(c) In 180g of sample = 6 moles of carbon

$\rightarrow$ In 1g of sample= $\dfrac{6}{180}$ moles of carbon

$\rightarrow So,$ In 1.245g of sample = $\dfrac{6}{180}\times1.245 = 0.0415$ moles

and mass of carbon in sample = 0.0415$\times$ 12 = 0.498g

(d) Moles of glucose in sample= $\dfrac{1.245}{180}= 6.916\times 10^{-3}moles$

Since, In 1 moles of sample contains 6.023$\times10^{23}molecules$

So, In $6.916\times10^{-3} moles$ or 1.245g of sample of glucose contains $6.91\times10^{-3} \times 6.023\times 10^{23}$

$\rightarrow 41.655\times10^{20}=4.1655\times10^{21}$ particles