To 300 g of a solution with a mass fraction of potassium carbonate 5% poured 300 g of a solution

To 300 g of a solution with a mass fraction of potassium carbonate 5% poured 300 g of a solution with a mass fraction of sulfuric acid 5%. Calculate the amount of gas evolved.

Given:

m (K2CO3) = 300 g

m (H2SO4) = 300 g

w% (K2CO3) = 5%

w% (H2SO4) = 5%

To find:

V (gas) -?

Decision:

K2CO3 = H2SO4 = K2SO4 + H2O + CO2, – we solve the problem based on the composed reaction equation:

1) Find the masses of potassium carbonate and sulfuric acid in solutions:

m (K2CO3) = 300 g * 0.05 = 15 g

m (H2SO4) = 300 g * 0.05 = 15 g

2) Find the amount of potassium carbonate and sulfuric acid:

n (K2CO3) = m: M = 15 g: 138 g / mol = 0.11 mol

n (H2SO4) = m: M = 15 g: 98 g / mol = 0.153 mol

We start from a lower value to get more accurate calculations. We work with K2CO3:

3) We compose a logical expression:

if 1 mol of K2CO3 gives 1 mol of CO2,

then 0.11 mol K2CO3 will give x mol CO2,

then x = 0.11 mol.

4) Find the volume released as a result of the reaction:

V (CO2) = n * Vm = 0.11 mol * 22.4 l / mol = 2.464 l.

Answer: V (CO2) = 2.464 l.