Iron weighing 6.72 g was burned in chlorine Cl2. Calculate the mass of the resulting iron chloride (3) FeCl3.

Let us write down the equation of the reaction for the formation of iron (III) chloride:

2Fe + 3Cl2 = 2FeCl3

Let’s find the amount of the substance Fe:

v (Fe) = m (Fe) / M (Fe) = 6.72 / 56 = 0.12 (mol).

According to the reaction equation, 2 mol of FeCl3 is formed from 2 mol of Fe, therefore:

v (FeCl3) = v (Fe) = 0.12 (mol).

Thus, the mass of the formed iron (III) chloride:

m (FeCl3) = v (FeCl3) * M (FeCl3) = 0.12 * 162.5 = 19.5 (g).

Answer: 19.5 g.