How to correctly arrange the coefficients in chemical reactions?

1. First, let’s write the reaction equation. For example: AlCl3 + AgNO3 —> AgCl + Al (NO3) 3
2. Further we see that we have 3 chlorine atoms, therefore, we must put this triple in the right side of the equation. It will turn out: AlCl3 + AgNO3 —> 3AgCl + Al (NO3) 3
3. Further, we notice that now we have not equalized silver and NO3. Since we have 3 NO3 ions and 3 silver atoms on the right side, then we put a triple in front of AgNO3 on the left side: AlCl3 + 3AgNO3 —> 3AgCl + Al (NO3) 3 Then it turns out that now all components are in equal amounts. But there are also reactions where you can determine the coefficients of the oxidation state. For example: P + O2 -> P2O5 Let’s arrange the oxidation states: P ^ 0 + O2 ^ 0 -> P2 ^ + 5O5 ^ -2 Next, we describe which substances change the degree of oxidation: P ^ 0 -> – 5e P ^ + 5 4 O2 ^ 0 -> + 2e * 2 2O ^ -2 5 Then we arrange the coefficients 4P + 5O2 -> 2P2O5