Find the mass of the precipitate that forms when 20 g of aluminum chloride react with sodium hydroxide

| September 19, 2021 | education

1.Let’s find the amount of substance aluminum chloride by the formula:

n = m: M.

M (AlCl3) = 27 + 105 = 132 g / mol.

n = 20 g: 132 g / mol = 0.15 mol.

2. Let’s compose the equation of the reaction between sodium hydroxide and aluminum chloride. Let’s determine in what quantitative ratios they are.

3NaOH + AlCl3 = 3NaCl + Al (OH) 3.

For 3 mol of sodium hydroxide, there is 1 mol of aluminum hydroxide (precipitates). The substances are in quantitative ratios of 3: 1. The amount of the sediment substance will be 3 times less than sodium hydroxide.

1 / 3n (Al (OH) 3) = n (NaOH) = 0.15: 3 = 0.05 mol.

3.Let’s find the mass of aluminum hydroxide by the formula:

m = n × M,

M (Al (OH) 3) = 27 + 3 (16 + 1) = 78 g / mol.

m = 0.05 mol × 78 g / mol = 3.9 g.

Answer: 3.9g.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.