Question

What are the coefficients needed to balance this chemical reaction to show that matter is conserved? fe + cl2 → fecl3

Answer 1

Let a, b, and c be the coefficients in the balanced reaction:

a Fe + b Cl₂   →   c FeCl₃

Count the atoms that show up among the reactants and products. They should be equal on both sides:

Fe : a = c

Cl : 2b = 3c

Let c = 2. Then a = 2 and 2b = 6, so b = 3.

Then the balanced reaction is

2 Fe + 3 Cl₂   →   2 FeCl₃