Question:medium
How many oxygen atoms are present in 0.36 g of a drop of water at STP?
How many oxygen atoms are present in 0.36 g of a drop of water at STP?
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Key Points:
Molar mass of H$_2$O $\approx$ 18 g/mol.
Avogadro's number (N$_A$) $\approx 6.022 \times 10^{23$ particles/mol.
Moles = Mass / Molar Mass.
Number of particles = Moles $\times$ N$_A$.
Determine the number of atoms of interest per molecule.
STP conditions usually apply to gas volume, not mass calculations for liquids/solids.
Updated On: Nov 28, 2025
- $6.023 \times 10^{22}$
- $1.205 \times 10^{22}$
- $6.023 \times 10^{23}$
- $1.205 \times 10^{23}$
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