By how much does the pressure of a gas in a rigid vessel decrease when the temperature drops from 0 ∘C to - 1∘C?

It needs 1 from Adeline mustafic

If the volume of the container doesn't change, then the pressure of

the gas inside is proportional to its absolute temperature. That's

the temperature on the Kelvin scale.

0°C = 273.16 K

-1°C = 272.16 K.

So the gas pressure drops to

(272.16 / 273.16) = 99.63%

of what it was initially, a precipitous plunge of 0.366 percent.