Question

a sealed vessel contains 15 kpa chlorine and 89 kpa fluorine in addition to some helium. the total pressure is 205 kpa. what is the partial pressure of helium in kpa?

Explanation:

Step1: Recall Dalton's Law

Total pressure = sum of partial pressures: $P_{\text{total}} = P_{\text{Cl}_2} + P_{\text{F}_2} + P_{\text{He}}$

Step2: Calculate partial pressure of He

Rearrange formula: $P_{\text{He}} = P_{\text{total}} - P_{\text{Cl}_2} - P_{\text{F}_2}$
Substitute values: $P_{\text{He}} = 205 - 15 - 89$

Step3: Compute the result

$205 - 15 = 190$; $190 - 89 = 101$

Answer:

101