Question

name: trisha date: 9/30/ icients. 10. c₂h₅oh + o₂ → co₂ + h₂o 11. mg + hcl → mgcl₂ + h₂

Explanation:

Step1: Balance carbon atoms

In $C_2H_5OH + O_2
ightarrow CO_2 + H_2O$, there are 2 carbon atoms in $C_2H_5OH$. So we put a 2 in front of $CO_2$: $C_2H_5OH + O_2
ightarrow 2CO_2 + H_2O$.

Step2: Balance hydrogen atoms

There are 6 hydrogen atoms in $C_2H_5OH$. So we put a 3 in front of $H_2O$: $C_2H_5OH + O_2
ightarrow 2CO_2+3H_2O$.

Step3: Balance oxygen atoms

On the left - hand side, we have 1 oxygen atom in $C_2H_5OH$ and 2 oxygen atoms in $O_2$. On the right - hand side, we have $2\times2 + 3\times1=7$ oxygen atoms. So we need 3 $O_2$ molecules on the left - hand side. The balanced equation is $C_2H_5OH + 3O_2
ightarrow 2CO_2+3H_2O$.

For the reaction $Mg + HCl
ightarrow MgCl_2 + H_2$:

Step1: Balance chlorine atoms

There are 2 chlorine atoms in $MgCl_2$. So we put a 2 in front of $HCl$: $Mg + 2HCl
ightarrow MgCl_2 + H_2$.

Step2: Check other elements

Magnesium and hydrogen are already balanced. The balanced equation is $Mg + 2HCl
ightarrow MgCl_2 + H_2$.

Answer:

$C_2H_5OH + 3O_2
ightarrow 2CO_2+3H_2O$; $Mg + 2HCl
ightarrow MgCl_2 + H_2$