A gas has a volume of 1.4 liters at STP. What is the new volume when the temperature is changed
to 40 K and the pressure is changed to 1.2 atm?

Answer : The new volume when the temperature is changed  to 40 K and the pressure is changed to 1.2 atm is, 0.17 L

Explanation :

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

where,

= initial pressure of gas at STP  = 1 atm

= final pressure of gas = 1.2 atm

= initial volume of gas at STP = 1.4 L

= final volume of gas = ?

= initial temperature of gas at STP = 273 K

= final temperature of gas = 40 K

Now put all the given values in the above equation, we get:

Therefore, the new volume when the temperature is changed  to 40 K and the pressure is changed to 1.2 atm is, 0.17 L