Calculate the mass of salt that forms when 4 g of NaOH reacts with CO2.

Given:

m (NaOH) = 4 g

To find:

m (salt) -?

Decision:

2NaOH + CO2 = Na2CO3 + H2O, – we solve the problem, relying on the composed reaction equation:

1) Find the amount of sodium hydroxide that has reacted:

n (NaOH) = m: M = 4 g: 40 g / mol = 0.1 mol

2) We compose a logical expression:

If 2 mol NaOH gives 1 mol Na2CO3,

then 0.1 mol NaOH will give x mol Na2CO3,

then x = 0.05 mol.

3) we find the mass of sodium carbonate formed during the reaction:

m (Na2CO3) = n * M = 0.05 mol * 106 g / mol = 5.3 g.

Answer: m (Na2CO3) = 5.3 g.