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llat it crosses the QUESTIONS AND PROBLEMS 1. (a) In the experiment, why are the

ID: 557357 • Letter: L

Question

llat it crosses the QUESTIONS AND PROBLEMS 1. (a) In the experiment, why are the water levels inside and outside the flask equalized before removing the flask from the cold water? (b) When the water level is higher inside than outsid e the lask, is the gas pressure in the flask higher than, lower than, or the same as, the atmospheric pressure? (specify which 2. A 125 mL sample of dry air at 230C is cooled to 100C at constant pressure. What volume will the dry air then occupy? ml of a gas is at 150°C: At what temperature will the gas occup 3. A 250. mL container a volume of 125 mL, the pressure remaining constant?

Explanation / Answer

1.(a) The water level outside and inside the flask is equalized before removing the flask from the cold water. This is done to equalize the pressure outside and inside of the flask. That is to equalize the pressure inside the flask with the atmospheric pressure.

(b). The gas pressure is lower inside the flask than the atmospheric pressure.

Answer : lower than atmospheric pressure.

2. V1 = 125 ml

T1 = 230oC + 273 = 503 K

T2 = 100oC + 273 = 372 K

P = constant

According to Charles law at constant pressure Volume Temperature

So, V1/T1 = V2/T2

V2 = V1T2/T1

V2 = (125 ml x 372K)/503K

V2 = 92.4 ml

Volume occupied by dry gas at 100oC = 92.4 ml

3. V1 = 250 ml

V2 = 125 ml

T1 = 150oC + 273 = 423 K

T2 = ???

P = constant

According to Charles law at constant pressure Volume Temperature

So, V1/T1 = V2/T2

T2 = V2T1/V1

T2 = (125 ml x 423K)/ 250 ml

T2 = 211.5 K

T2 = 273 – 211.5 = - 61.5 oC

Final T = - 61.5 oC