A balloon is inflated to 7.0 L of volume. How many moles of gas does it contain at standard temperature and pressure (STP)?

• A. 0.31 mol
• B. 1.0 mol
• C. 2.2 mol
• D. 0.16 mol

Answer: (A)

Verified step by step guidance

1. Identify the known values: volume \(V = 7.0\ \text{L}\), and conditions are at standard temperature and pressure (STP). At STP, the temperature is \$0^\circ C$ (273.15 K) and pressure is 1 atm.
2. Recall the molar volume of an ideal gas at STP, which is \$22.4\ \text{L/mol}$. This means 1 mole of an ideal gas occupies 22.4 liters at STP.
3. Use the relationship between volume and moles at STP: \(n = \frac{V}{22.4}\), where \(n\) is the number of moles and \(V\) is the volume in liters.
4. Substitute the given volume into the formula: \(n = \frac{7.0}{22.4}\) to find the number of moles of gas in the balloon.
5. Perform the division to calculate \(n\), which will give the amount of gas in moles contained in the balloon at STP.