Question

A balloon at the top of Mount Logan occupies a volume of 775mL at a temperature of -28°C and a pressure of 92.5kPa. What is the pressure at the bottom of the mountain if the same balloon has a volume of 825mL at a temperature of 15°C? 

Answer 1

-28^oC = 273 - 28 = 245 K

15^oC = 273 + 15 = 288 K

According to the combined gas law,

$\frac{p_1V_1}{T_1}=\frac{p_2V_2}{T_2}$

Therefore,

$p_2=\frac{p_1V_1T_2}{T_1V_2}=\frac{92.5kPa\times775mL\times288K}{245K\times825mL}=102kPa$

Answer: 102 kPa