Chemistry Examples

$K M n O_{4} + Z n + H C l \to M n C l_{2} + K C l + Z n C l_{2} + H_{2} O$

Step 1

The law of conservation of mass states that matter cannot be created nor destroyed. There are no more or less atoms at the end of a chemical reaction than there were at the beginning. To balance a chemical equation, every element must have the same number of atoms on each side of the equation.

To balance a chemical equation:

1. Every element must have the same number of atoms on each side of the equation (law of conservation of mass).

2. Balancing the equation can be done only by adjusting the coefficients.

Step 2

$K$ is a balanced element because there is the same number of atoms of $K$ in each side of the equation.

$K$ is a balanced element

Step 3

$M n$ is a balanced element because there is the same number of atoms of $M n$ in each side of the equation.

$M n$ is a balanced element

Step 4

$O$ is not a balanced element. To balance $O$ , multiply $H_{2} O$ from the right side by $4$ .

$K M n O_{4} + Z n + H C l \to M n C l_{2} + K C l + Z n C l_{2} + 4 H_{2} O$

Step 5

$Z n$ is a balanced element because there is the same number of atoms of $Z n$ in each side of the equation.

$Z n$ is a balanced element

Step 6

$H$ is not a balanced element. To balance $H$ , multiply $H C l$ from the left side by $8$ .

$K M n O_{4} + Z n + 8 H C l \to M n C l_{2} + K C l + Z n C l_{2} + 4 H_{2} O$

Step 7

$C l$ is not a balanced element. To balance $C l$ , multiply $H C l$ from the left side by $16$ and $M n C l_{2}, K C l, Z n C l_{2}$ from the right side by $2$ .

$K M n O_{4} + Z n + 16 H C l \to 2 M n C l_{2} + 2 K C l + 2 Z n C l_{2} + 4 H_{2} O$

Step 8

$K$ is not a balanced element. To balance $K$ , multiply $K M n O_{4}$ from the left side by $2$ .

$2 K M n O_{4} + Z n + 16 H C l \to 2 M n C l_{2} + 2 K C l + 2 Z n C l_{2} + 4 H_{2} O$

Step 9

$M n$ is a balanced element because there is the same number of atoms of $M n$ in each side of the equation.

$M n$ is a balanced element

Step 10

$O$ is not a balanced element. To balance $O$ , multiply $4 H_{2} O$ from the right side by $2$ .

$2 K M n O_{4} + Z n + 16 H C l \to 2 M n C l_{2} + 2 K C l + 2 Z n C l_{2} + 8 H_{2} O$

Step 11

$Z n$ is not a balanced element. To balance $Z n$ , multiply $Z n$ from the left side by $2$ .

$2 K M n O_{4} + 2 Z n + 16 H C l \to 2 M n C l_{2} + 2 K C l + 2 Z n C l_{2} + 8 H_{2} O$

Step 12

$H$ is a balanced element because there is the same number of atoms of $H$ in each side of the equation.

$H$ is a balanced element

Step 13

$C l$ is not a balanced element. To balance $C l$ , multiply $16 H C l$ from the left side by $16$ and $2 M n C l_{2}, 2 K C l, 2 Z n C l_{2}$ from the right side by $2$ .

$2 K M n O_{4} + 2 Z n + 16 H C l \to 2 M n C l_{2} + 2 K C l + 4 Z n C l_{2} + 8 H_{2} O$

Step 14

$K$ is a balanced element because there is the same number of atoms of $K$ in each side of the equation.

$K$ is a balanced element

Step 15

$M n$ is a balanced element because there is the same number of atoms of $M n$ in each side of the equation.

$M n$ is a balanced element

Step 16

$O$ is a balanced element because there is the same number of atoms of $O$ in each side of the equation.

$O$ is a balanced element

Step 17

$Z n$ is not a balanced element. To balance $Z n$ , multiply $2 Z n$ from the left side by $2$ .

$2 K M n O_{4} + 4 Z n + 16 H C l \to 2 M n C l_{2} + 2 K C l + 4 Z n C l_{2} + 8 H_{2} O$

Step 18

$H$ is a balanced element because there is the same number of atoms of $H$ in each side of the equation.

$H$ is a balanced element

Step 19

$C l$ is not a balanced element. To balance $C l$ , multiply $16 H C l$ from the left side by $16$ and $2 M n C l_{2}, 2 K C l, 4 Z n C l_{2}$ from the right side by $5$ .

$2 K M n O_{4} + 4 Z n + 16 H C l \to 2 M n C l_{2} + 2 K C l + 5 Z n C l_{2} + 8 H_{2} O$

Step 20

$K$ is a balanced element because there is the same number of atoms of $K$ in each side of the equation.

$K$ is a balanced element

Step 21

$M n$ is a balanced element because there is the same number of atoms of $M n$ in each side of the equation.

$M n$ is a balanced element

Step 22

$O$ is a balanced element because there is the same number of atoms of $O$ in each side of the equation.

$O$ is a balanced element

Step 23

$Z n$ is not a balanced element. To balance $Z n$ , multiply $4 Z n$ from the left side by $5$ and from the right side by $4$ .

$2 K M n O_{4} + 5 Z n + 16 H C l \to 2 M n C l_{2} + 2 K C l + 5 Z n C l_{2} + 8 H_{2} O$

Step 24

$H$ is a balanced element because there is the same number of atoms of $H$ in each side of the equation.

$H$ is a balanced element

Step 25

$C l$ is a balanced element because there is the same number of atoms of $C l$ in each side of the equation.

$C l$ is a balanced element

Step 26

All elements have the same number of atoms in each side of the equation, which means that the law of conservation of mass is satisfied and the chemical equation is balanced.

$2 K M n O_{4} + 5 Z n + 16 H C l \to 2 M n C l_{2} + 2 K C l + 5 Z n C l_{2} + 8 H_{2} O$