Question

balance the following equations: 1. mg + o2 → mgo 2. cucl2 + h2s → cus + hcl

Explanation:

Step1: Balance the first equation

For the reaction $Mg + O_2
ightarrow MgO$, there are 2 oxygen atoms on the left - hand side and 1 oxygen atom in $MgO$ on the right - hand side. To balance the oxygen atoms, we put a 2 in front of $MgO$. Then, to balance the magnesium atoms, we put a 2 in front of $Mg$. The balanced equation is $2Mg+O_2 = 2MgO$.

Step2: Balance the second equation

For the reaction $CuCl_2 + H_2S
ightarrow CuS + HCl$, there are 2 chlorine atoms in $CuCl_2$ and 1 chlorine atom in $HCl$. So we put a 2 in front of $HCl$. The balanced equation is $CuCl_2 + H_2S=CuS + 2HCl$.

Answer:

1. $2Mg+O_2 = 2MgO$
2. $CuCl_2 + H_2S=CuS + 2HCl$