CHEM 1211 Gases-Part 1 Worksheet 4-2. Name(s):

Transcription

1 CHEM 1211 Gases-Part 1 Worksheet 4-2 Name(s): Pressure [1] The atmospheric pressure at the summit of Mt. McKinley is 581 mmhg on a certain day. What is the pressure in atmospheres, in atmospheres and in bars? [2] On a certain day the barometer in a laboratory indicates that the atmospheric pressure is torr. A sample of gas is placed in a flask attached to an open-end mercury manometer. The difference in heights of the mercury columns (h) is found to be 32.6 mm. What is the pressure of the gas in mmhg [3] Atmospheric pressure is 759 mmhg. The pressure in the flask is 705 mmhg. What is the height difference in the Hg columns? Which diagram correctly represents this (one on left or one on the right) [4] Calculate the height of a column of ethylene glycol that would be supported by atmospheric pressure (760 mmhg). The density of ethylene glycol is 1.2 g/ml Gas Laws: [5] Circle the plot that does not correctly represent Boyle s Law. [6] A fixed quantity of gas at 298 K exhibits a pressure of 735 mmhg at a volume of 5.22-L. What is the pressure if the volume is increased to 7.55-L

2 [7] A balloon is filled with 0.70-L of a gas at 298 K and a pressure of 1.2-atm. What is the new volume of the balloon if the temperature is dropped to 77 K (liquid nitrogen temperature) at constant pressure? [8] Determine the pressure change when a constant volume of gas at 1.00 atm is heated from 20.0 C to 80.0 C. [9] At a certain temperature and pressure 1.00 mole of He gas occupies 505-mL a) What volume would a mole of SF6 gas occupy at that same temperature and pressure. b) What volume would 3.50 moles of He gas occupy at the this temperature and pressure? [10] Consider the following gaseous sample in a cylinder filled with a movable piston. Initially there are n moles of the gas at temperature, T, pressure, P, and volume, L. Choose the cylinder that correctly represents the gas after each of the following changes: 1) P is tripled at constant n and T 2) T(K) is doubled at constant n and P 3) n more moles of gas are added at constant T(K) and P 4) T(K) is halved at constant P and n [11] An inflated balloon has a volume of 6.0 L at sea level (1.0 atm) and is allowed to ascend in altitude until the pressure is 0.45 atm. During ascent the temperature of the gas falls from 22 C to 21 C. Calculate the volume of the balloon at its final altitude

3 [12] A 25.0-L storage flask is filled with 247-mmHg of a gas at 30 C. If the total volume is increased to 45.5-L and the temperature is increased to 50 C, what is the resulting pressure in mmhg [13] A sample of Ar gas in a 15.0-L container exerts a pressure of atm at 355 K. Calculate the moles of Ar gas in the container. [14] Given that 6.9 moles of carbon monoxide gas are present in a container of volume 30.4 L, what is the pressure of the gas (in atm) if the temperature is 82 C Gas Mixtures [15] Determine the partial pressure of each gas (The relative amounts are depicted) [16] How is the pressure exerted by N2 gas affected when some O2 is introduced into a container at constant temperature and volume? [17] A container holds a mixture of oxygen, neon, and helium gases whose partial pressures are 150 torr, 300 torr, and 450 torr, respectively. The mole fraction of neon is.

4 [18] To help prevent the bends, He is mixed with O2 in scuba tanks. For a particular dive, 46 L of He at 25 C and 1.0 atm and 12 L O2 at 25 C and 1.0 atm were pumped into a tank with a volume of 5.0 L. Calculate the partial pressure of each gas and the total pressure in the tank at 25 C? a) What is the partial pressure of each gas in this mixture? (Hint: Boyle s Law) b) What is the total pressure of this mixture? c) What is the mole fraction of He in this mixture? [19] Determine the total pressure (in torr) when the stopcock is opened. (Assume a total final volume of 3.00 L). [20] Consider the following gas samples at the same temperature. Rank these in order of increasing: (The larger boxes are 2 the smaller ones, group equivalent samples in { }.) a) Pressure b) Density

5 [21] A 2.10-L vessel contains 4.65 g of a gas at 1.00 atm and 27.0 C. a) Calculate the density of the gas in g/l. b) What is the molar mass of the gas? [22] The density of N2O (FW = 44.01) at 1.53 atm and 318K is g/l [23] Consider two different containers, each filled with 2.0 moles of Ne. One of the containers is ridged and has constant volume. The other container is flexible (like a balloon) and is capable of changing its volume to keep the external pressure and internal pressure equal to each other. If you raise the temperature in both containers what happens to density of the gas inside each container? Assume a constant external pressure. [24] At constant temperature and pressure, 16 L of N2 and 48 L of H2 are mixed. Assuming all the reactants are consumed, how many L of NH3 will be produced? N2(g) + 3H2(g) 2NH3(g)