Question

calculate the mass of Na(in kg) present in 95kg of a crude sample of NaNO3,whose percentage purity is 70%.​

Answer 1

We have to calculate the mass of Na ( in Kg) present in 95kg of of a crude sample of NaNO₃ , whose percentage purity is 70 %.

solution : actual mass of NaNO₃ in sample = mass of crude sample of NaNO₃ × percentage purity

= 95 × 70/100

= 95 × 7/10

= 66.5 Kg

molecular weight of NaNO₃ = 23 + 14 + 3 × 16 = 23 + 14 + 48 = 85 g

atomic weight of Na = 23 g

we see, 23 g of Na contains in 85g of NaNO₃

so, in 66.5 kg of NaNO₃ contains 23/85 × 66.5 kg = 18 kg of Na.

Therefore 18 kg Na present in 95 kg of a crude sample of NaNO₃ whose percentage purity is 70%