Question

Calculate the number of particles in: (i) 8g of O2 molecules (ii) 2.5 mol of
calcium atoms.

Answer 1

Answer:

Explanation:

(i) 32g of O2 have molecules = 6.022 X 10^23

So, 8g of O2 have molecules = (6.022 X 10^23/32) x 8

                                                  =  1.5 x 10^23 molecules

(ii) 1 mol of calcium have a       = 6.022 X 10^23 atoms

So, 2.5 mol of calcium have a = 6.022 X 10^23 x 2.5

                                                  = 15.055 x10 ^23 atoms

Answer 2

(i) 32g of O2 have molecules = 6.022 X 10^23

So, 8g of O2 have molecules = (6.022 X 10^23/32) x 8

                                                 =  1.5 x 10^23 molecules

(ii) 1 mol of calcium have a       = 6.022 X 10^23 atoms

So, 2.5 mol of calcium have a = 6.022 X 10^23 x 2.5

                                                 = 15.055 x10 ^23 atoms