Answer:
2KClO3(s) + heat → 2KCl(s) + 3O2(g)
Step-by-step explanation:
KClO3(s) + heat → KCl(s) + O2(g)
Adding coefficients so that there are 6 O atoms on both sides.
2KClO3(s) + heat → KCl(s) + 3O2(g)
Balancing K and Cl atoms, there are 2 of each on the left and 1 of each on the right.
2KClO3(s) + heat → 2KCl(s) + 3O2(g)
The equation is now balanced.