# After 240 g of a 25% sodium hydroxide solution, 33.6 liters of carbon dioxide were passed. What is the mass fraction of NaHCO3 Decision:
M (NaOH) = 40 g / mol;
VM = 22.4 liters
m (NaOH) = [m (solution). W%] / 100% = (240. 25) / 100 = 60 g.
Then
m (H2O) = m (p-pa) – m (NaOH) = 240 – 60 = 180 g.
n (NaOH) = m (NaOH) / M (NaOH) = 60/40 = 1.5 mol.
n (CO2) = V / VM = 33.6 / 22.4 = 1.5 mol.
The reaction equation has the form:
NaOH + CO2 ↔ NaHCO3
It follows from the equation that 1 mol of CO2 reacts with 1 mol of NaOH and in this case 1 mol of NaHCO3 is formed:
n (NaOH) = n (NaOH) = n (NaHCO3) = 1.5 mol.
So, in this case, all carbon dioxide and sodium hydroxide completely reacted, and only sodium bicarbonate is present in the solution.
Calculate the mass of NaHCO3, we get:
m (NaHCO3) = M (NaHCO3). n (NaHCO3) = 84. 1.5 = 126 g.
We find the mass of the resulting solution, which will be the remaining water and sodium bicarbonate, we obtain:
m (solution) = m (H2O) + m (NaHCO3) = 180 + 126 + 306 g.
w% (NaHCO3) = (126.100) / 306 = 41.18%. Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.