Calculate the percentage of water of crystallisation in the sample of washing soda, `Na_(2)CO_(3).10H_(2)O`.

Explanation

To calculate the percentage of water of crystallization in washing soda, \( \text{Na}_2\text{CO}_3 \cdot 10\text{H}_2\text{O} \), we will follow these steps:

### Step 1: Determine the molar mass of washing soda
The molar mass of washing soda consists of the molar masses of its constituent elements:

- Sodium (Na): There are 2 sodium atoms. The molar mass of sodium is approximately 23 g/mol.
\[
\text{Mass of Na} = 2 \times 23 = 46 \, \text{g/mol}
...