Determine the mass of the sediment that forms when calcium chloride is poured with 40 g of 5% sodium carbonate solution.

Given:
m solution (Na2CO3) = 40 g
w (Na2CO3) = 5% = 0.05
To find:
m (CaCO3)
Decision:
Na2CO3 + CaCl2 = CaCO3 + 2NaCl
m in-islands (Na2CO3) = w * m solution = 0.05 * 40 g = 2 g
n (Na2CO3) = m / M = 2 g / 106 g / mol = 0.02 mol
n (Na2CO3): n (CaCO3) = 1: 1
n (CaCO3) = 0.02 mol
m (CaCO3) = n * M = 0.02 mol * 100 g / mol = 2 g
Answer: 2 g