Question

a sample of carbon dioxide gas occupies 3.5 L at 25degrees C. At what temperature will the gas volume be 1 L?

Answer 1

V1/T1 = V2/T2
Use T in Kelvin.

Answer 2

v2xt1/v1=t2
1x298/3.5=85.1k

Answer 3

If your teacher is picky about significant figures, I think you are allowed only two (from the 3.5) and I assume the 1 L actually is 1.0 L. If so, I would round to 85 K.