Question

balance each equation and list the coefficients in the balanced equation going from reactants to products.
a. mg(s) + n₂(g) → __mg₃n₂(s)

1. 1, 3, 2 2) 3, 1, 2 3) 3, 1, 1

b. al(s) + cl₂(g) → __alcl₃(s)

1. 3, 3, 2 2) 1, 3, 1 3) 2, 3, 2

Explanation:

Step1: Balance equation A

Count atoms on both sides. For Mg, we need 3 Mg on reactant side to match 3 in $Mg_3N_2$. For $N_2$, 1 molecule provides 2 N atoms which match $Mg_3N_2$. So the balanced equation is $3Mg(s)+N_2(g)\longrightarrow Mg_3N_2(s)$ with coefficients 3, 1, 1.

Step2: Balance equation B

For Al, we need 2 Al on reactant side to match 2 in $AlCl_3$. For $Cl_2$, 3 molecules provide 6 Cl atoms which match 6 in $2AlCl_3$. So the balanced equation is $2Al(s) + 3Cl_2(g)\longrightarrow2AlCl_3(s)$ with coefficients 2, 3, 2.

Answer:

A. 3, 1, 1
B. 2, 3, 2