Quiz 5/4/041. For what purpose is a

manometer used?2. Explain how a gas exerts

pressure on its container.3. Which gas exerts less

pressure, the one on the right or the left?

4. What is the value of standard atmospheric pressure in kPa.

5. If the difference in height in the manometer on the left is 25 mm, and atmospheric pressure is 100 kPa, what is the pressure of the gas in the left manometer?

6. Convert 25oC to Kelvins.

Gas molecules bounce against the sidesof the container, Pressure = Force/Area therefore,the more collisions, the more pressure.

A manometer is used to measure gas pressure.

101.3 kPa

The gas on the left exerts less pressure

Pgas = 100 – 25/7.5Pgas = 97 kPa

25oC + 273 = 298 K

States of matter

Gases move rapidly filling the entire container.

Gases form when atomsdo not have enough attractiveforce to stay near each other.

Liquids consist of disorganized atoms/moleculeswhich are attracted to each other.

Solids are organized structureswith lots of attraction and little“freedom” to move

most movement

leastmovement

Test Tomorrow

• Today: To study for the test, write three questions and their answers.

1. a question about an open ended manometer, including a calculation.

2. a question about a closed end manometer, including a calculation.

3. a question relating kelvin temperatures to celcius temperatures.

4. extra credit : 5 simple questions.

# 25. An open manometer like the one in figure 15.4 is used to measure the pressure of a gas sample. The mercury level is 12 mm higher in the gas

sample arm. What is the pressure, in kilopascals,of the gas in the container if the air pressure is 98.7 kilopascals?

• Patm = 98.7 – 12/7.5

• Patm = 97.1 kPa

# 26. In a closed manometer, assume that the height of the levels differs by 522 mm Hg. What is the pressure, in kilopascals, of the gas

in the container?

• Pgas = 522/7.5

• Pgas = 69.6 kPa

Answers to the rest of the questionsare:27. 103.5 kPa28. 106.7 kPa29. The temperature increasesdirectly (proportionally) with an increasein Kinetic energy.30. Absolute zero means all molecularmotion ceases (stops).

Homework where work is shown only merits ½ credit!

More practice.

a. 186K

b. 192 K

c. 433 K

d. 421 K

e. 894 K

= -87oC

= - 81oC

= 160oC

= 148oC

= 621oC

- 273K

- 273K

- 273K

- 273K

- 273K

10. a. 123oC

b. -90oC

c. 18oC

d. 25oC

+ 273K = 396 K

+ 273K = 331 K

+ 273K = 291 K

+ 273K = 298 K

Which gas moves slowest, at StandardTemperature andPressure?12. N2 = 28g/mole F2 = 38 g/mole CO2 = 44g/mole O2 = 32 g/mole

N2 moves the fastestbecause it weighs theleast. CO2 moves slowest.