The mass of one molecule of water is `x xx 10^(-23)` g. The value of x is:

Explanation

To find the value of \( x \) in the mass of one molecule of water expressed as \( x \times 10^{-23} \) g, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Mass of Water**:
The molar mass of water (H₂O) is known to be 18 grams per mole. This means that one mole of water weighs 18 grams.

2. **Use Avogadro's Number**:
One mole of any substance contains \( 6.022 \times 10^{23} \) molecules (Avogadro's number). Therefore, 18 grams of water contains \( 6.022 \times 10^{23} \) molecules of water.

3. **Calculate the Mass of One Molecule**:
To find the mass of one molecule of water, we can divide the total mass of one mole of water by the number of molecules in one mole:
\[ \text{Mass of one molecule of H₂O} = \frac{18 \, \text{g}}{6.022 \times 10^{23}} \]

4. **Perform the Calculation**:
\[ \text{Mass of one molecule of H₂O} \approx \frac{18}{6.022 \times 10^{23}} \approx 2.99 \times 10^{-23} \, \text{g} \]

5. **Express in the Required Format**:
The mass can be rounded to \( 3 \times 10^{-23} \, \text{g} \). Therefore, in the expression \( x \times 10^{-23} \, \text{g} \), we find that \( x = 3 \).

### Conclusion:
The value of \( x \) is \( 3 \).

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