# Calculate the mass and amount of the substance of the formed salt if copper (II) oxide with a mass of 8 g

Calculate the mass and amount of the substance of the formed salt if copper (II) oxide with a mass of 8 g was added to a solution of hydrochloric acid weighing 36.5 g and mass fraction of HCL 10%.

Reaction of hydrochloric acid with copper oxide.
2HCl + CuO = CuCl2 + H2O.
Find the mass of the acid contained in a 10% solution.
m (HCl) = W (HCl) • m (solution) / 100% = 10% • 36.5 g / 100% = 3.65 g.
Let’s calculate the number of moles of the starting materials.
n (CuO) = m / Mr = 8 g / 80 g / mol = 0.1 mol.
n (HCl) = 3.65 g / 2 x 36.5 = 0.05 mol.
Copper oxide is taken in excess, therefore, the calculation is carried out on a shortage.
The mass of copper chloride is.
m (CuCl2) = n • Mr = 0.05 mol • 134.5 g / mol = 6.725 g. 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.