Question:
The mass of one molecule of water is approximately
The mass of one molecule of water is approximately
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Always divide molar mass by Avogadro number to get molecular mass.
Updated On: Apr 24, 2026
- $8 \times 10^{-26}$ kg
- $6.5 \times 10^{-26}$ kg
- $3.5 \times 10^{-28}$ kg
- $2.5 \times 10^{-28}$ kg
- $3 \times 10^{-26}$ kg
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The Correct Option is
Solution and Explanation
Concept:
• Mass of one molecule: \[ m = \frac{\text{molar mass}}{N_A} \]
Step 1: Molar mass of water
\[ = 18 \times 10^{-3} \, kg \]
Step 2: Use Avogadro number
\[ N_A = 6.022 \times 10^{23} \]
Step 3: Compute
\[ m = \frac{18 \times 10^{-3}}{6.022 \times 10^{23}} \approx 3 \times 10^{-26} kg \] Final Conclusion:
Option (E)
• Mass of one molecule: \[ m = \frac{\text{molar mass}}{N_A} \]
Step 1: Molar mass of water
\[ = 18 \times 10^{-3} \, kg \]
Step 2: Use Avogadro number
\[ N_A = 6.022 \times 10^{23} \]
Step 3: Compute
\[ m = \frac{18 \times 10^{-3}}{6.022 \times 10^{23}} \approx 3 \times 10^{-26} kg \] Final Conclusion:
Option (E)
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