You have a sample of gas in a flask with a volume of 250 mL. At 25.5 degrees Celcius, the pressure of the gas is 300 mm Hg. If you decrease the temperture to -5.0 degrees celcius, what is the gas pressure at this lower temperture?

P1/T1 = P2/T2.

Don't forget to change celsius to Kelvin. Note the correct spelling of Celsius.

hbi

To find the gas pressure at the lower temperature, you can use the combined gas law.

The combined gas law states that the ratio of the product of pressure and volume to the product of temperature and moles (which remains constant), is the same before and after the change in conditions.

Before we proceed, we need to convert the temperatures from Celsius to Kelvin since the gas law equations require temperatures in Kelvin.

Given:
Initial volume (V1) = 250 mL
Initial temperature (T1) = 25.5 degrees Celsius
Initial pressure (P1) = 300 mm Hg

Final temperature (T2) = -5.0 degrees Celsius
New pressure (P2) = ?

First, let's convert the temperatures to Kelvin:
T1 (in Kelvin) = T1 (in Celsius) + 273.15
= 25.5 + 273.15
= 298.65 K

T2 (in Kelvin) = T2 (in Celsius) + 273.15
= -5.0 + 273.15
= 268.15 K

Now, we can use the combined gas law equation:
(P1 * V1) / T1 = (P2 * V1) / T2

Substituting the known values:
(300 mm Hg * 250 mL) / 298.65 K = (P2 * 250 mL) / 268.15 K

Now, solve for P2:
P2 = (300 mm Hg * 250 mL * 268.15 K) / (298.65 K * 250 mL)

P2 ≈ 267.67 mm Hg

Therefore, at the lower temperature of -5.0 degrees Celsius, the gas pressure is approximately 267.67 mm Hg.