Exp. E-1A A. Obtain a pressure-measuring device as indicated by your lab instructor. Obtain a 60 mL syringe, fill it with air, and connect the syringe to the gas-measuring device as indicated in the figure. Test your apparatus for gas leaks. If you can’t eliminate all leaks, see your lab instructor. B. If necessary, calibrate your gas-measuring device as indicated by your lab instructor. Fill your syringe to the largest volume mark on the syringe and reconnect to the gas-measuring device. What is the pressure of the trapped air in the syringe?
Explain. -The pressure of the trapped air in syringe is 0. 01 bar or 0. 00987 atm. The pressure of trapped gas is equal to the pressure of the atmosphere because it is measured relative to the atmospheric pressure. C. Depress the plunger of the syringe and describe the system. Is the pressure of the trapped air greater or less than the atmospheric pressure? Explain. – The pressure of the trapped air is higher than the atmospheric pressure. Since the gas are being compressed inside the syringe, and reducing its volume.
This will caused the molecules to hit the container more often since there isn’t much space. The frequent collision between the gas molecules and the container causes a rise in pressure. D. Release the plunger of the syringe. Adjust the plunger to the 60mL mark. Record the pressure reading of the trapped air in the following table. Atmospheric pressure = 732 torr at 9:00 A. M, November 6, 2012. Pressure (bar) Pressure (atm) Volume (mL) 0. 04 0. 0395 60 0. 15 0. 1480 54 0. 29 0. 2863 48 0. 46 0. 4540 42 0. 68 0. 6713 36 1. 00 1. 0130 30 1. 45 1. 4314 24 2.
13 2. 1027 18 2. 52 2. 4877 12 2. 80 2. 7640 6 II. Data Analysis A. If necessary, calculate the total pressure of the trapped air for each reading and record it in the following table. Show how you calculate this pressure for your first reading in the space below. Total Pressure = Pressure from reading + atmospheric pressure (732/760 = 0. 963atm) Total pressure of the enclosed gas is the atmospheric pressure plus the pressure that produced by excess air. B. Calculate the total volume of the trapped air for each reading and record it in the following table.
Show how you calculated this volume for your first reading. Total volume = The syringe volume + (pi * r^2) Note: diameter of the syringe is 2. 54cm. So the radius is 1. 27cm. Total Pressure (atm) Total Volume (arbitrary units ) 0. 0395 + 0. 963 = 1. 0025 60 + (pi * 1. 27^2) = 65. 067 1. 1110 59. 07 1. 2493 53. 07 1. 4170 47. 07 1. 6343 41. 07 1. 9760 35. 07 2. 3944 29. 07 3. 0657 23. 07 3. 4507 17. 07 3. 7270 11. 07 C. What patterns are shown in these data? Graph the data and try to come up with an algebraic equation that expresses the pattern you found.
As pressure increases, volume will decrease. III. Data Interpretation A. How are the pressure and volume of gas sample related? For a given number of moles of gas molecules, the pressure is inversely proportional to the volume if the temperature is held constant. Which means that if pressure is increased, volume will decreased. Pressure x volume = constant. When volume shrinks, gas molecules have less space to travel and hit their container more often, this creates higher pressure. B.
Mental Model – Draw a picture(s) that explains how the pressure and volume of a gas sample are related at the level of atoms and molecules and that illustrates the observations you made in the experiment. In words, explain how your pictures illustrates this relationship. – When the volume shrinks due to more pressure pushed down. Then gas molecules will have less space to move and therefore hit the container more often. The more frequently the gas hits the walls of the container, the higher the pressure it will creates.