Topic 5 - Kinetic Theory and Gases

Question 1

How are the particles arranged in a solid?

Answer 1

• Strong forces of attraction hold particles together in fixed, regular arrangement
• Particles don’t have much energy so can only vibrate about their fixed positions

Question 2

How are the particles arranged in a liquid?

Answer 2

• Weaker forces of attraction between particles
• Particles are close together but can move past each other + form irregular arrangements
• Have more energy than particles in solids so move in random directions at low speeds

Question 3

How are the particles arranged in a gas?

Answer 3

• Almost no forces of attraction between particles
• Particles have more energy than those in liquids/solids
• Free to move + travel in random directions at high speeds
• Consist of very small particles (kinetic theory)
• Particles constantly moving + colliding w/ each other + walls of container
• When they collide, bounce off each other or walls
• Hardly take up any space, most of the gas is empty space

Question 4

What are the three states of matter?

Answer 4

• Solid
• Liquid
• Gas

Question 5

What is absolute zero?

Answer 5

• Increase temp = higher KE, decrease temp = lower KE
• Coldest possible temp
• As little kinetic energy as possible to get
• 0K

Question 6

How do you convert from kelvin to °C?

Answer 6

-273

Question 7

How do you convert from °C to kelvin?

Answer 7

+273

Question 8

For every 1°C increase, how many kelvins does it increase by?

Answer 8

1

Question 9

What is absolute zero in °C and kelvin?

Answer 9

• -273°C

- 0K

Question 10

What is the freezing point of water in °C and kelvin?

Answer 10

• 0°C

- 273K

Question 11

What is the boiling point of water in °C and kelvin?

Answer 11

• 100°C

- 373K

Question 12

What is the relationship between kinetic energy and temperature?

Answer 12

• Kelvin temperature of a gas is directly proportional to average kinetic energy of its particles
• If increase temp, particles have more energy, double temp = double average KE

Question 13

What does the kinetic theory say about colliding gas particles?

Answer 13

• As gas particles move they collide w/ each other/anything else in their way
• Gas particles are very light but not massless so when collide exert force on it
• In sealed container gas particles hit container walls creating outward pressure
• Pressure depends on how fast particles are moving + how often hit walls

Question 14

What is the relationship between volume and temperature of a gas when pressure is constantly?

Answer 14

Proportional (heat up particles have more energy so move faster expanding + taking yo more room, so volume increases)

Question 15

What is the equation linking volume and temperature when pressure is constant?

Answer 15

Volume1 = (volume2 x temperature p1) / temperature2
Temperature must be in K
V1=(V2xT1)/T2
V1 + T1 are starting conditions + V2 + T2 and final conditions
V/T=constant

Question 16

What is the relationship between pressure and volume at a constant temperature?

Answer 16

• Inversely proportional
• As pressure increases, volume decreases + vice versa
• Bigger container has fewer collisions between gas particles + container walls o

Question 17

What is the equation to show the relationship between pressure and volume at a constant temperature?

Answer 17

V1 x P1 = V2 x P2
Fixed mass
V1 + P1 = initial volume + pressure, V2 + P2 = final volume + pressure

Question 18

How can you use a gas syringe to investigate volume and temperature at a constant pressure?

Answer 18

• Half full gas syringe w/ air + seal w/ rubber bung
• Use Bunsen burner to heat air in gas syringe
• As it heats, gas expands, pushing plunger outwards, volume of gas increases as temp increases
• Since syringe plunger free to move pressure of gas always same
• If cooled again gas will contract pulling plunger in