To calculate the number of moles in 30 grams of water (H₂O), you can use the formula:
\[ \text{Number of moles} = \frac{\text{mass (grams)}}{\text{molar mass (g/mol)}} \]
First, find the molar mass of water (H₂O):
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Hydrogen (H) has a molar mass of about 1.01 g/mol, and there are 2 hydrogen atoms: \[ 2 \times 1.01 , \text{g/mol} = 2.02 , \text{g/mol} \]
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Oxygen (O) has a molar mass of about 16.00 g/mol.
Now, add the masses together to get the molar mass of water: \[ \text{Molar mass of H₂O} = 2.02 , \text{g/mol} + 16.00 , \text{g/mol} = 18.02 , \text{g/mol} \]
Next, use this molar mass to calculate the number of moles in 30 grams of water: \[ \text{Number of moles} = \frac{30 , \text{grams}}{18.02 , \text{g/mol}} \approx 1.66 , \text{moles} \]
So, there are approximately 1.66 moles of water in 30 grams.