How many moles are present in 100.0 g of water (H_2O)?

• A. 5.55 moles
• B. 3.33 moles
• C. 1.80 moles
• D. 0.555 moles

Answer: (A)

Verified step by step guidance

1. Identify the given quantity and the substance: You have 100.0 grams of water (H\_2O).
2. Calculate the molar mass of water by adding the atomic masses of its elements: Hydrogen (H) has an atomic mass of approximately 1.00 g/mol, and Oxygen (O) has an atomic mass of approximately 16.00 g/mol. So, molar mass of H\_2O = (2 \times 1.00) + 16.00 = 18.00 g/mol.
3. Use the formula to find moles from mass: \(\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}\).
4. Substitute the known values into the formula: \(\text{moles} = \frac{100.0}{18.00}\).
5. Perform the division to find the number of moles of water in 100.0 g.