Question

When the volume of a gas is changed from 800 cm3 to 400 cm3 the temperature will change from 115 C to ___C

Answer 1

(115 + 273) K x (400 cm^3 / 800 cm^3) = 194 K = −79°C

Answer 2

Answer: The final temperature of the system comes out to be -79°C

Explanation:

To calculate the final temperature of the system, we use the equation given by Charles' Law.

This law states that volume of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

$\frac{V_1}{T_1}=\frac{V_2}{T_2}$

where,

$V_1\text{ and }T_1$ are the initial volume and temperature of the gas.

$V_2\text{ and }T_2$ are the final volume and temperature of the gas.

We are given:

$V_1=800cm^3\\T_1=115^oC=(115+273)K=388K\\V_2=400cm^3\\T_2=?$

Putting values in above equation, we get:

$\frac{800cm^3}{388K}=\frac{400cm^3}{T_2}\\\\T_2=194K$

Converting the temperature from kelvins to degree Celsius, by using the conversion factor:

$T(K)=T(^oC)+273$

$194=T(^oC)+273\\T(^oC)=-79^oC$

Hence, the final temperature of the system comes out to be -79°C