which chemical equation is a balanced chemical equation?
c+s -> cs2
2503 -> 2502 + o2
2nh3 -> n2 + 2h2
2c + o2 -> co2

None

Explanation:

None of these equations are balanced. To determine if an equation is balanced, count the number of each element on each side. If the product side (right) equals the reactant side (left), then an equation is balanced.

To count atoms, multiply its subscript (the small number if it has one) with the coefficient (the big number if it has one).

C + S => CS₂

C 1           C 1

S 1            S 2

The "S" sulphur atoms are not balanced.

25O₃ => 25O₂ + O₂

O 75             O 52

The "O" oxygen atoms are not balanced.

2NH₃ => N₂+ 2H₂

N 2                N 2

H 6                H 4

The "H" hydrogen atoms are not balanced.

2C + O₂ => CO₂

C 2               C 1

O 2               O 2

The "C" carbon atoms are not balanced.

Balancing equations

Write coefficients until both sides have the same number of atoms. Each time you make a change, recount the number of atoms. Here are the balanced chemical equations: (I wrote in bold and underline)

C + 2S => CS₂

2O₃ => 2O₂ + O₂

2NH₃ => N₂ + 3H₂

2C + 2O₂ => 2CO₂