The interaction of ethanol weighing 13.8 g with copper oxide (2) weighing 28 g gave an aldehyde. calculate its mass.

Let’s find the amount of substance CuO.

n = m: M.

M (CuO) = 80 g / mol.

n = 28 g: 80 g / mol = 0.35 mol.

Let’s find the amount of substance C2H5OH.

n = m: M.

M (C2H5OH) = 46 g / mol.

n = 13.8 g: 46 g / mol = 0.3 mol.

Let’s find the quantitative ratios of substances.

C2Н5OH + CuO = СН3СОН + Cu + Н2О.

CuO is given in excess, we solve by C2H5OH

For 1 mol of C2H5OH, there is 1 mol of CH3COH.

Substances are in quantitative ratios 1: 1.

The amount of substance will be equal.

n (СН3СОН) = n (C2Н5OH) = 0.3 mol.

Let us find the mass of СН3СОН.

M (CH3CHOH) = 44 g / mol.

m = n × M.

m = 44 g / mol × 0.3 mol = 13.2 g.

Answer: 13.2 g.