A motorist discovers that her auto tire measures 29.2 psi rather than the recommended 35 psi. If the tire' s volume is assumed constant at 11.6 L and the temperature is 45 ° F at the filling station, how many moles of air will the motorist need to add to bring the tire to 35 psi? (assume 1.00 atm = 14.7 psi )

Question

Quizplus · Accepted Answer

To find the moles of air needed, use the ideal gas law: PV = nRT. Convert pressures from psi to atm (29.2 psi = 1.986 atm, 35 psi = 2.381 atm). The change in pressure is 0.395 atm. Convert temperature to Kelvin (45°F = 280.37 K). Use R = 0.0821 L·atm/mol·K. Calculate the change in moles: Δn = (ΔP * V) / (R * T) = (0.395 atm * 11.6 L) / (0.0821 L·atm/mol·K * 280.37 K) ≈ 0.2 moles.

A Motorist Discovers That Her Auto Tire Measures 29