9.26 Assume that you have a sample of gas in a cylinder with a movable piston, as shown in the following drawing: Redraw the apparatus to show what the sample will look like after (a) the temperature is increased from 300 K to 450 K at constant pressure, (b) the pressure is increased from 1 atm to 2 atm at constant temperature, and (c) the temperature is decreased from 300 K to 200 K and the pressure is decreased from 3 atm to 2 atm.

9. 27. Assume that you have a sample of gas at 350 9.27 Assume that you have a sample of gas at 350 K in a sealed container, as represented in (a). Which of the drawings (b)–(d) represents the gas after the temperature is lowered from 350 K to 150 K?

9.28 Assume that you have a mixture of He (atomic ) and Xe (atomic ) at 300 K. Which of the drawings best represents the mixture (blue = He; green = Xe)?

9.29 Three bulbs, two of which contain different gases and one of which is empty, are connected as shown in the following drawing: Redraw the apparatus to represent the gases after the stopcocks are opened and the system is allowed to come to equilibrium.

9.30 The apparatus shown is called a closed-end manometer because the arm not connected to the gas sample is closed to the atmosphere and is under vacuum. Explain how you can read the gas pressure in the bulb.

9.31 Redraw the following open-end manometer to show what it would look like when stopcock A is opened.

9.32 Effusion of a 1:1 mixture of two gases through a small pinhole produces the results shown below. (a) Which gas molecules—yellow or blue—have a higher average speed? (b) If the yellow molecules have a molecular mass of 25 amu, what is the molecular mass of the blue molecules?

9.33 A glass tube has one end in a dish of mercury and the other end closed by a stopcock. The distance from the surface of the mercury to the bottom of the stopcock is 800 mm. The apparatus is at 25°C, and the mercury level in the tube is the same as that in the dish. (a) Show on drawing (1) what the approximate level of mercury in the tube will be when the temperature of the entire apparatus is lowered from +25°C to 25°C. (b) Show on drawing (2) what the approximate level of mercury in the tube will be when a vacuum pump is connected to the top of the tube, the stopcock is opened, the tube is evacuated, the stopcock is closed, and the pump is removed. Show on drawing (3) what the approximate level of mercury in the tube will be when the stopcock in drawing (2) is opened. (c)