Question

Assume a 5g page is made up entirely of one polysaccaride cellulose molecule (CnH2nOn), where n can be a quite large number. the atomic weights of C, H, and O are 12, 1, and 16 respectivley. How many carbon atoms are there in this page?

Answer 1

emperical formula = CnH2nOn

for example if n=1;

then the formula will be CH₂O

molecular weight of this formula is 12+2+16 = 30;

number of moles = weight/molecular weight

if number of moles = 1, then weight = molecular weight

that means weight of one mole of CH₂O = 30 grams

what is the number of moles of 5 grams of CH₂O = ?

= 5/30 = 0.16 moles

that means 0.16 moles of CH₂O are present in 5g of page.

In one mole, there are 6.022 x 10²³ atoms, so in 0.16 moles, there are 6.022 x 10²³x 0.16

carbon atoms present.

Number of carbons in 0.16moles of CH₂O = 9.635 x 10²²