how many atoms of each type are present in 143 grams of washing soda

Gram molecular mass of Na2CO3 = 106 g

so 106g of Na₂CO₃ = 1mol

  143g of Na₂CO₃ = 143 / 106 = 1.35 mol

 

Now, 1 mol of Na₂CO₃ contains = 2 x 6.022 x 10²³ atoms of sodium

so   1.35 mol of Na₂CO₃ contains = 1.35 x 2 x 6.022 x 10²³

                                               = 16.25 x 1023 Na atoms

 

1 mol of Na₂CO₃ contains = 6.022 x 10²³ atoms of carbon

1.35 mol would have = 1.35 x 6.022 x 10²³

                              = 8.13 x 10²³ carbon atoms

 

1 mol of Na₂CO₃ contains = 3 x 6.022 x 1023 atoms of oxygen

1.35 mol would have = 1.35 x 3 x 6.022 x 10²³

                              = 24.39 x 10²³ oxygen atoms