Chemistry Examples

$K_{2} C O_{3}$

Step 1

To find the mass of $1$ mole of $K_{2} C O_{3}$ look up the atomic mass of each element and multiply it by the number of atoms contained in each element in the molecule.

mass of $1$ mole of $K_{2} C O_{3}$ $=$ $2 (mass of K)$ + $(mass of C)$ + $3 (mass of O)$

Step 2

Fill in the atomic masses from the periodic table.

mass of $1$ mole of $K_{2} C O_{3}$ $=$ $2 (39.09999847)$ + $(12.01000022)$ + $3 (16)$

Step 3

Simplify the result.

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Step 3.1

Remove parentheses.

mass of $1$ mole of $K_{2} C O_{3} = 2 (39.09999847) + 12.01000022 + 3 (16) g$

Step 3.2

Simplify each term.

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Step 3.2.1

Multiply $2$ by $39.09999847$ .

mass of $1$ mole of $K_{2} C O_{3} = 78.19999694 + 12.01000022 + 3 (16) g$

Step 3.2.2

Multiply $3$ by $16$ .

mass of $1$ mole of $K_{2} C O_{3} = 78.19999694 + 12.01000022 + 48 g$

Step 3.3

Simplify by adding numbers.

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Step 3.3.1

Add $78.19999694$ and $12.01000022$ .

mass of $1$ mole of $K_{2} C O_{3} = 90.20999717 + 48 g$

Step 3.3.2

Add $90.20999717$ and $48$ .

mass of $1$ mole of $K_{2} C O_{3} = 138.20999717 g$

Step 4

Find the mass percentage of $K$ .

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Step 4.1

The mass composition percentage is the mass of $K$ divided by the mass of the entire molecule converted to a percentage.

Mass percentage of $K = \frac{78.2}{138.20999717} \cdot 100$

Step 4.2

Divide $78.2$ by $138.20999717$ .

$0.56580566 \cdot 100$

Step 4.3

Multiply $0.56580566$ by $100$ .

$56.58056696$

Step 4.4

Set the number as a percent.

Mass percentage of $K = 56.58056696 %$

Step 5

Find the mass percentage of $C$ .

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Step 5.1

The mass composition percentage is the mass of $C$ divided by the mass of the entire molecule converted to a percentage.

Mass percentage of $C = \frac{12.01}{138.20999717} \cdot 100$

Step 5.2

Divide $12.01$ by $138.20999717$ .

$0.08689675 \cdot 100$

Step 5.3

Multiply $0.08689675$ by $100$ .

$8.6896753$

Step 5.4

Set the number as a percent.

Mass percentage of $C = 8.6896753 %$

Step 6

Find the mass percentage of $O$ .

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Step 6.1

The mass composition percentage is the mass of $O$ divided by the mass of the entire molecule converted to a percentage.

Mass percentage of $O = \frac{48}{138.20999717} \cdot 100$

Step 6.2

Divide $48$ by $138.20999717$ .

$0.34729759 \cdot 100$

Step 6.3

Multiply $0.34729759$ by $100$ .

$34.72975977$

Step 6.4

Set the number as a percent.

Mass percentage of $O = 34.72975977 %$

Step 7

Find the mass percentage of each element in the molecule.

Mass percentage of $K = 56.58056696 %$

Mass percentage of $C = 8.6896753 %$

Mass percentage of $O = 34.72975977 %$

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