Question

Calculate the mass of oxygen in grams for 5.188 kilograms of iron(III) carbonate?

Answer 1

Molar mass of Fe2(CO3)3,

MM = 2*MM(Fe) + 3*MM(C) + 9*MM(O)

= 2*55.85 + 3*12.01 + 9*16.0

= 291.73 g/mol

mass(Fe2(CO3)3)= 5.188 Kg

= 5188.0 g

use:

number of mol of Fe2(CO3)3,

n = mass of Fe2(CO3)3/molar mass of Fe2(CO3)3

=(5.188*10^3 g)/(2.917*10^2 g/mol)

= 17.78 mol

This is number of moles of Fe2(CO3)3

one mole of Fe2(CO3)3 contains 9 mole of O

use:

number of moles of O = 9 * number of moles of Fe2(CO3)3

= 9 * 17.78

= 1.601*10^2

Molar mass of O = 16 g/mol

use:

mass of O,

m = number of mol * molar mass

= 1.601*10^2 mol * 16 g/mol

= 2.561*10^3 g

=  2.561 Kg

Answer: 2.561 Kg