How many moles of He gas are present in 500 L at standard temperature and pressure (STP)?

• A. 500 mol
• B. 22.3 mol
• C. 0.446 mol
• D. 22.3 mol

Answer: (D)

Verified step by step guidance

1. Recall that at standard temperature and pressure (STP), one mole of any ideal gas occupies a volume of 22.4 liters. This is a key concept known as the molar volume of a gas at STP.
2. Write down the given volume of helium gas: 500 liters.
3. Use the relationship between volume and moles at STP: \(\text{moles} = \frac{\text{volume of gas (L)}}{\text{molar volume at STP (L/mol)}}\).
4. Substitute the known values into the formula: \(\text{moles} = \frac{500\, \text{L}}{22.4\, \text{L/mol}}\).
5. Perform the division to find the number of moles of helium gas present in 500 liters at STP.