What is the mass of the precipitate formed by the interaction of 20 g of a 15% sodium
What is the mass of the precipitate formed by the interaction of 20 g of a 15% sodium chloride solution with an excess of silver nitrate solution?
Find the mass of sodium chloride in the solution.
W = m (substance): m (solution) × 100%, hence
m (substance) = (m (solution) × W): 100%.
m (substance) = (20 g × 15%): 100% = 3 g.
Find the amount of magnesium nitrate NaCl by the formula:
n = m: M.
M (NaCl) = 58.5 g / mol.
n = 3 g: 58.5 g / mol = 0.05 mol.
Let’s compose the reaction equation, find the quantitative ratios of substances.
NaCl + AgNO3 = AgCl ↓ + NaNO3.
According to the reaction equation, 1 mol of NaCl accounts for 1 mol of AgCl. Substances are in quantitative ratios 1: 1.
The amount of substance will be equal.
n (AgCl) = n (NaCl) = 0.05 mol.
Let us find the mass of AgCl.
M (AgCl) = 143.5 g / mol.
m = n × M.
m = 143.5 g / mol × 0.05 mol = 7.175 g.
Answer: 7.175 g.