Question

Find the mass of the following: (i) 3.011x10^23 atoms of oxygen (ii) 6.022x10^24 molecules of oxygen. (Given atomic mass of O=16u; No= 6.022x10^23 per mole)

Answer 1

(i) 8 g

(ii) 160 g

Step-by-step explanation:

(i)

Convert the molecules into the number of moles.

3.011x10^23 / 6.022x10^23 = 0.5

There is 0.5 mol of oxygen.

Mass = mol x Mr

Mr of oxygen = 16

0.5 x 16 = 8

(ii)

Convert the amount of molecules into the number of moles.

6.022x10^24 / 6.022x10^23 = 10

There are 10 mols of oxygen

10 x 16 = 160