Question

When the volume of a gas is
changed from 3.6 L to 15.5 L, the
temperature will change from
°C to 87°C.
Assume that the number of moles and the
pressure remain constant.
Be sure to notice that temperatures are
given in °C!

Answer 1

Initial temperature = -189.4  °C

Further explanation

Given

the volume of a gas is  changed from 3.6 L to 15.5 L

final temperature = 87 °C = 87+ 273 = 360 K

Required

initial temperature

Solution

Charles's Law

When the gas pressure is kept constant, the gas volume is proportional to the temperature  

$\tt \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}$

$\tt T_1=\dfrac{V_1.T_2}{V_2}\\\\T_1=\dfrac{3.6\times 360}{15.5}\\\\T_1=83.6~K=-189.4^oC$