Agas is contained in a thick walled balloon. when the pressure change from __ torr to 777 torr, the volume changes from 2.58 l to 1.53 l and the temperature changes from 368 k to 495 k.

Let's assume that the gas is an ideal gas.

Then we can use combined gas law,

 PV/T = k (constant)

Where, P is the pressure of the gas, V is volume of the gas and T is the temperature of the gas in Kelvin.

For two situations, we can use that as,

P₁V₁/T₁= P₂V₂/T₂

P₁ = ?

V₁ =  2.58 L

T₁ = 368 K

P₂ = 777 torr

V₂ = 1.53 L

T₂ = 495 K

By applying the formula,

   P₁ x 2.58 L / 368 K = 777 torr x 1.53 L / 495 K

                             P₁ = 342.6 torr

Hence, the answer is 342.6 torr.

1.solid

2.carbon dioxide

3.helium

what is the question here. i think you messed up.