Question

Oxygen gas having a volume of 1000 cm³ at 40.0 o C and 1.01×10⁵ Pa expands until its volume is 1500 cm³ and its pressure is 1.06×10⁵ Pa. Find the number of moles of oxygen present.

Answer 1

To find the number of moles of oxygen present, use the ideal gas law equation PV = nRT. Convert temperatures to Kelvin and pressures to atmospheres. Plug the values into the equation and solve for n, the number of moles of oxygen. The number of moles of oxygen present is approximately 4.16 moles.

Step-by-step explanation:

To find the number of moles of oxygen present, we can use the ideal gas law equation: PV = nRT.

1. Convert the given temperatures to Kelvin by adding 273.15. The initial temperature is 40.0°C, so it becomes 313.15 K. The final temperature is 25.0°C, so it becomes 298.15 K.
2. Convert the given pressures to atmospheres by dividing by 101325. The initial pressure is 1.01×10⁵ Pa, so it becomes 0.997 atm. The final pressure is 1.06×10⁵ Pa, so it becomes 1.045 atm.
3. Plug the values into the equation: (0.997 atm)(1000 cm³) = n(0.0821 L·atm/mol·K)(313.15 K)
4. Solve for n, the number of moles of oxygen.

The number of moles of oxygen present is approximately 4.16 moles.