Answer:
1) 0 C2H4O2 + 0 O2 -> 0 CO2 + 0 H2O (balanced)
2) V2O5 + CaS -> CaO + V2S5
just additional info: V2O5 is divanadium pentaoxide
LHS (Left hand side)
V: 2
O: 5
Ca: 1
S: 1 x 5 [to balance with the right hand side of the equation]
RHS (Right hand side)
V: 2
O: 1 x 5 [to balance with the left hand side of the equation]
Ca: 1
S: 5
When you balance any elements, you have to balance the whole chemical compound.
Thus,
V2O5 + 5 CaS -> 5 CaO + V2S5
LHS CHECK:
V: 2
O: 5
Ca: 5
S: 5
RHS CHECK:
V: 2
O: 5
Ca: 5
S: 5
3) S8 + O2 -> SO2
LHS:
S: 8
O: 2
RHS:
S: 1 x 8 [to balance with LHS]
O: 2
When you balance any elements, you have to balance the whole chemical compound.
S8 + O2 -> 8 SO2
When we add 8 to the RHS, it gives us 8S, 16 O.
In order to balance that into the RHS, I need to multiply the O2 by 8, which will give 8(O2) = 16 O particles.
Therefore, S8 + 8 O2 -> 8 SO2 is the final answer for (3).