Gas laws PPT

Question 1

2 main factors determine state:

Answer 1

• The forces (inter/intramolecular) holding particles together

• the kinetic energy present(the
energy an object possesses due to its motion of the particles)

Question 2

This tends to pull particles apart

Answer 2

Kinetic energy

Question 3

These have a higher kinetic energy because their particles move a lot more than in a solid or a liquid

Answer 3

Gases

Question 4

As the temperature increases, the gas particles move faster, and thus kinetic energy ____

Answer 4

increases

Question 5

Characteristics of Gases (5)

Answer 5

1. Gases expand to fill any container
   -random motion, no attraction
2. Gases are fluids (like liquids)
   - no attraction
3. Gases have very low densities
   -no volume = lots of empty space
4. Gases can be compressed
   -no volume = lots of empty space
5. Gases undergo diffusion and effusion (across a barrier with small holes).
   -random motion

Question 6

Particles in an ideal gas….

Answer 6

• have no volume.
• have elastic collisions (ie. billiard ball-> particles exchange energy with eachother, but total KE is conserved
• are in constant, random, straight-line motion.
• don’t attract or repel each other.
• have an avg. KE directly related to temperature

Question 7

Particles in a REAL gas…

Answer 7

• have their own volume
• attract each other (intermolecular forces)

Question 8

Gas behavior is most ideal at

Answer 8

• at low pressures
• at high temperatures

Question 9

At STP, molecules of gas are moving ___ and are very ____, making their intermolecular forces and volumes _____, so assumptions of an ideal gas are valid under normal temp/pressure conditions. BUT…..

Answer 9

fast

far apart

insignificant

• at high pressures: gas molecules are pushed closer together, and their interactions with each other become more significant due to volume

• at low temperatures: gas molecules move slower due to KE and intermolecular forces are no longer negligible

Question 10

Pressure

Answer 10

Pressure = force/area

Question 11

The gas molecules in the atmosphere are ____ toward Earth due to gravity, exerting ____

Answer 11

pulled

pressure

Question 12

measures atmospheric pressure

Answer 12

Barometer

Question 13

At Standard Atmospheric Pressure
(SAP)

Answer 13

101.325 kPa (kilopascal)
1 atm (atmosphere)
760 mm Hg (millimeter Hg)
760 torr
14.7 psi (pounds per square inch)

Question 14

kPa equation

Answer 14

kPa = N/m2

Question 15

Standard Temperature and Pressure

Answer 15

0 C or 273 K

1 atm or 101.325 kPa

Question 16

Scottish physicist ____ suggested that -273°C (OK) was the temperature at which the motion particles within a gas approaches zero.. And thus, so does volume)

Answer 16

Lord Kelvin

Question 17

Does everything freeze at 0°C?

Answer 17

No, not everything freezes at 0C but for ALL substances, motion stops at 0 K

Question 18

Why use Kelvin Scale?

Answer 18

It eliminates the use of negative values for temperature! Makes mathematic calculations possible (to calculate the temp. twice warmer than -5°C we can’t use 2x(-
5°C) because we would get -10°C!)