Intro To Molecules And Gas Laws

Question 1

What determines if a reaction will take place?

Answer 1

Thermodynamics - change in energy

Question 2

What determines how fast a reaction occurs?

Answer 2

Kinetics - rates, orders, mechanisms

Question 3

What determines how ‘complete’ a reaction is?

Answer 3

Equilibria - governed by thermodynamics

Question 4

What is one of the main aims of physical chemistry?

Answer 4

To describe chemical systems numerically

Question 5

What is the defining characteristic of gases?

Answer 5

The pressure they exert

Question 6

What is the pressure (p) exerted by a gas dependent on?

Answer 6

• The amount of gas present (n)
• The volume in which it is contained (V)
• Temperature (T)

Question 7

At what temperature are atoms/molecules in motion?

Answer 7

• At any temperature above absolute zero (K)

Question 8

At a molecular level what is pressure?

Answer 8

The collective result of the forces exerted my atoms/molecules through never-ending collisions with each other and the walls of their container

Question 9

What did Boyle determine?

Answer 9

That volume was inversely proportional to pressure (for a fixed mass of gas at a constant temperature.)

Question 10

What is Boyle’s Law?
(Equation)

Answer 10

Question 11

What did Charles determine?

Answer 11

That the volume of gas is directly proportional to its temperature

Question 12

What is Charles’ Law?
(Equation)

Answer 12

Question 13

What did Avogadro determine?

Answer 13

That the gas volume is directly proportional to the amount of gas

Question 14

What is Avogadro’s law?
(Equation)

Answer 14

Question 15

What is the Ideal Gas Equation?

Answer 15

Question 16

What assumptions does the Ideal Gas Equation operate upon?

Answer 16

• Particles do not interact
• Particles occupy zero volume
• “Ideal” Behaviour

Question 17

What are the units of Temperature?

Answer 17

K = kelvin

Question 18

What are the units of Pressure?

Answer 18

Pa = pascals

Question 19

What are the units of Volume?

Answer 19

Meters cubed = m^3

Question 20

What type of equation is the Ideal Gas Equation?

Answer 20

It is an Equation of State

Question 21

What assumptions does the ideal gas equation make?

Answer 21

• A gas has negligible forces between its constituent atoms or molecules
• Gas atoms or molecules have negligible volumes

Question 22

Do real gases follow ideal behaviour?

Answer 22

No

Question 23

Who made a correction to the gas equation in 1873?

Answer 23

Van der Waal

Question 24

What did the Van der Waals equation account for?

Answer 24

• Attractive forces
• Molecular volumes

Question 25

What is van der Waals equation?
(Equation)

Answer 25

Question 26

What does the “a” in van der Walls equation correct for?

Answer 26

• “a” corrects for reduced pressure due to intermolecular attractions

Question 27

What does the “b” in van der Waals equation correct for?

Answer 27

• “b” corrects volume for the volume lost to molecular size

Question 28

Why is Van der Waals correction important?

Answer 28

• Because at high pressure gases express more ‘real’ characteristics