At 127°c,400ml of a gas exerts a pressure of 120 torr. What would be the pressure exerted by 200ml of a gas if the temperature decrease to 27°c?

180 Torr.

Explanation:

Step 1:

Data obtained from the question. This include the following:

Initial temperature (T1) = 127 °C

Initial volume (V1) = 400 mL

Initial pressure ( P1) = 120 Torr

Final volume (V2) = 200 mL

Final temperature (T2) = 27 °C

Final pressure (P2) =..?

Step 2:

Conversion of celsius temperature to Kelvin temperature.

This is illustrated below:

Temperature (Kelvin) = Temperature (celsius) + 273

T(K) = T(°C) + 273

Initial temperature (T1) = 127 °C

Initial temperature (T1) = 127 °C + 273 = 400 K

Final temperature (T2) = 27 °C

Final temperature (T2) = 27 °C + 273 = 300 K

Step 3:

Determination of the final pressure.

This can be obtained by using the general gas equation as shown below:

Initial temperature (T1) = 400 K

Initial volume (V1) = 400 mL

Initial pressure ( P1) = 120 Torr

Final volume (V2) = 200 mL

Final temperature (T2) = 300 K

Final pressure (P2) =..?

P1V1/T1 = P2V2/T2

120 x 400/400 = P2 x 200/300

120 = P2 x 2/3

Cross multiply

P2 x 2 = 120 x 3

Divide both side by 2

P2 = (120 x 3)/2

P2 = 180 Torr.

Therefore, the new pressure exerted by the gas is 180 Torr.