Becca Liebendorfer,

Christine Davenport,

Ray Mai, Aliza Edelstein.

C-block

Gas Laws (Chapter 5)

Key Terms-

Pressure (P)- the force exerted per unit of surface area. P= force/area

Barometer- common device used to measure atmospheric pressure

Manometer- device used to measure the pressure of a gas in an experiment

Pascal (Pa)- SI unit of pressure

Standard atmosphere (atm)- another unit of pressure (large)

Millimeter of mercury (mmHg)- common pressure unit based on measurement with a barometer or manometer

1 torr= 1mmHg= 1/760atm= 101.325/760kPa= 133.322Pa

Ideal gas- exhibits simple linear relationships among volume, pressure temperature and amount

Boyle’s Law- V [is directly proportional to] 1/P (T and n fixed)

-at constant temperature, the volume occupied by a fixed amount of gas is inversely proportional to the applied [external] pressure

Charles’s Law- V [is directly proportional to] T (P and n fixed)

-at constant pressure, the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature

Avogadro’s Law- V [is directly proportional to] n (P and T fixed)

-at fixed temperature and pressure, equal volumes of any ideal gas contain equal numbers of particles (or moles)

standard temperature and pressure (STP)- 0°C (273.15K) and 1atm (760 torr)

standard molar volume- 22.4141L or 22.4L (to 3SF)

ideal gas law- PV=nRT

universal gas constant (R)- a proportionality constant

8.314 kPa*L/mol*K= 0.08206 L*atm/mol*K= 62.36mmHg*L/mol*K

partial pressure- portion of the total pressure of the mixture, that is the same pressure it would exert by itself

Dalton’s Law of partial pressure- in a mixture of unreacting gases, the total pressure is the sum of the partial pressure of the individual gas

Mole fraction (x)- component in a mixture contributes a fraction of the total number of moles in the mixture

Kinetic molecular theory- draws conclusions through mathematical derivations

RMS speed- A molecule moving at this speed has the average kinetic energy

Effusion- the process by which a gas escapes from its container through a tiny hole into an evacuated

Graham’s Law of effusion- the rate of effusion of a gas is inversely proportional to the square root of its molar mass

Diffusion- the movement of one gas though another

  1. What is the density of a gas that is 1.996g with a volume of 1190cm3?
  2. .001677g/L
  3. 1.677g/L*
  4. 596.2L/g
  5. .5962L/g
  6. 3.200 g of a gas is 5.080 moles. What is its molar mass?
  7. 1.588 g/mol
  8. 16.26 g/mol
  9. .6299g/mol*
  10. 5.015x10-24 g/mol
  11. Oxygen gas effuses through a capillary in 2.00 seconds. An unknown gas of the same volume effuses in 4.00 seconds. What is the molar mass of the unknown gas?
  12. .0156 g/mol*
  13. .0313 g/mol
  14. 32.00 g/mol
  15. 64.00 g/mol
  16. In a closed end manometer, the mercury level was 540.mm higher on the closed end than on the gas end. What was the gas pressure?
  17. 1290 mmHg
  18. 210. mmHg
  19. 440. mmHg
  20. 540. mmHg*
  21. If the Thirsty Bird (think Gay Lussac’s gas law) dips his head in water and cools down from 50◦C to 30◦C, and the pressure in his belly was originally 1 atm, what was the pressure after his drink?
  22. 1.67 atm
  23. .938 atm*
  24. 1.07 atm
  25. .600 atm
  26. A snake balloon has .00100 moles of air in it and a volume of .100 mL. If I blow .028 moles of air into it, what is its volume?
  27. 2.80 L
  28. 28.0 L*
  29. .0357 L
  30. .3571 L
  31. T1=207K. T2=301K. n1=.400 moles. n2=.275 mol. Which law is this?
  32. Unnamed*
  33. Boyles’
  34. Charles’
  35. Graham’s
  36. An He molecule, weighing 4.0 g/mol at 200K has ____times as much K.E. as an H2 molecule, weighing 2.0 g/mol, at 200K?
  37. 1.00 times as much*
  38. 2.00 times as much
  39. .500 times as much
  40. 0. times as much
  41. H2 molecules (2.00 g/mol) at 200.K go ____as fast as He molecules (4.00 g/mol) at 600.K?
  42. .667 times as fast
  43. 6.00 times as fast
  44. 2.45 times as fast
  45. .817 times as fast*
  46. Charles’ law: a gas with a volume of 700.mL at 300.K has what volume at 383K?
  47. 621 L
  48. 789 L
  49. .789 L
  50. .621 L

Gas Law Questions

In an open end manometer with an atmospheric pressure of 37.8 kPa, the Hg level was 27.3 mm higher on the left. What is the gas pressure?

  1. 3.64 kPa
  2. 22.3 kPa
  3. 34.2 kPa *
  4. 35.8 kPa

At 27 degrees Celsius, a gas, was at 321 kPa, at what temperature would it be at 1.00 atm?

  1. 710 Kelvin *
  2. 435 Kelvin
  3. 813 Kelvin
  4. 127 Kelvin

7.36 grams of a gas occupies 2.67 liters at 17 degrees Celsius and 115.2 kPa. How many moles of gas is it?

a. .449 moles

b. .120 moles

c. .372

d. .132 moles*

What is the density of MgO at 731 K in 7.32 psi?

  1. .491 g/l
  2. .334 g/l*
  3. .234 g/l
  4. .329g/l

What is the molecular weight of a gas that has a mass of 13.2 grams, a volume of 3.7 liters, at 32 degrees Celsius, and 117 kPa?

  1. 68.2 g/mol
  2. 77.3 g/mol*
  3. 60.8g/mol
  4. 79.9 g/mol