How many moles are there in 7.20g of H 2 O?
CHEMISTRY
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How many moles are there in 7.20g of H2O?
- A) 0.20
- B) 0.80
- C) 0.60
- D) 0.40
Correct Answer: D) 0.40
Explanation
To calculate the number of moles in 7.20g of H\(_2\)O, we first need to find the molar mass of H\(_2\)O. The molar mass is the sum of the atomic masses of all the atoms in the compound. In this case, H\(_2\)O consists of two hydrogen atoms (H) and one oxygen atom (O).
The atomic mass of hydrogen is approximately 1g/mol, and the atomic mass of oxygen is approximately 16g/mol. So, the molar mass of H\(_2\)O is:
\(2 \times 1 + 16 = 18\text{g/mol}\)Now, we can use the formula for calculating the number of moles:
\(\text{moles} = \frac{\text{mass}}{\text{molar mass}}\)Substitute the given mass (7.20g) and the molar mass of H\(_2\)O (18g/mol) into the formula:
\(\text{moles} = \frac{7.20\text{g}}{18\text{g/mol}}\)Perform the calculation:
\(\text{moles} = 0.40\)So, there are0.40 moles of H\(_2\)O in 7.20g of the compound, which corresponds toOption D.
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