## Chemistry and Chemical Reactivity (9th Edition)

Assuming that the temperature remains constant: $n_{He}=P_1V_1/RT$ $n_{Ar}=P_2V_3/RT$ $n_{He}+n_{Ar}=P_f(V_1+V_2)/RT=P_1V_1/RT+P_2V_2/RT$ $P_f=(P_1V_1+P_2V_2)/(V_1+V_2)$ $P_f=229\ mmHg$ $P_{He}=P_1V_1/(V_1+V_2)=87\ mmHg$ $P_{Ar}=P_2V_2/(V_1+V_2)=142\ mmHg$