Calculate the mass of the precipitate formed during the interaction of 9, 8 g of sulfuric acid 20 g of barium chloride.

Given:

m (H2SO4) = 9.8 g;

m (BaCl2) = 20 g.

To find:

m (BaSO4) =?

Decision:

1) We compose the equation of the chemical reaction:

H2SO4 + BaCl2 = BaSO4 (precipitate) + 2HCl.

2) Find which substance is in excess and which is in short supply. To do this, we determine the amount of substance of each compound, according to the formula: n = m: M.

M (H2SO4) = 2 + 32 + 64 = 98 g / mol.

M (BaCl2) = 137 + 71 = 208 g / mol.

n (H2SO4) = 9.8 g: 98 g / mol = 0.1 mol (excess).

n (BaCl2) = 20 g: 208 g / mol = 0.09 mol (deficiency).

3) The calculation is carried out for a disadvantage.

M (BaSO4) = 137 + 16 + 64 = 233 g / mol.

Let the mass of BaSO4 be x g, then:

20 g: 208 g / mol = x g: 233 g / mol, hence x = (20 x 233): 208 = 22.4 g.

Answer: m (BaSO4) = 22.4 g.