Question

a sample of gas occupies 100ml at 27degree C and 740mm pressure. the temprature of the gas will have,when its volume is changed into80ml at 740mm .then the pressure is_?

Answer 1

the pressure will be  -33°C.

Answer 2

pressure is constant hence from charles's law
V1/T1 =V2/T2
V1 = 100ml , T1 = 273+27 = 300k ,V2 = 80ml ,T2 = ?
T2 = 80*300/100
    = 240k
t2 = 240 - 273
    = -33°c