Chapter 1.1 Gases

Question 1

What is pressure measured in?

Answer 1

pascal, bar or atmosphere

Question 2

What is 1 Pascal (Pa) equal to?

Answer 2

force/area (N m^-2)

Question 3

What is 1 bar equivalent to in Pascals?

Answer 3

1 bar = 10^5 Pa = 100 kPa

Question 4

What is 1 atmosphere equivalent to in Pascals?

Answer 4

101.325 kPa

Question 5

How do particles of a molecule behave in the solid state?

Answer 5

fixed position with only vibrational motion

Question 6

When is the force holding a solid together in a lattice strong? When is it weak?

Answer 6

Strong - ionic solids

Weak - inert gases

Question 7

What is the correlation between interactive forces and melting point for a solid?

Answer 7

stronger interaction = ↑ melting point = more energy to break bonds

Question 8

What is the correlation between vibrational energy and temperature?

Answer 8

↑ temp = ↑ vibrational energy

Question 9

When is vibrational energy present in a solid?

Answer 9

ALWAYS - even at absolute zero (0ºK)

Question 10

When does the melting point of a solid occur?

Answer 10

magnitude of vibrational modes OVERCOME attractive forces = atoms/molecules lose their fixed position and become LIQUID

Question 11

How do particles behave in a liquid state?

Answer 11

The attraction between atoms or molecules keeps them touching and particles take the shape of the container due to slightly more motion

Question 12

How does density relate to liquids and solids?

Answer 12

Solids are usually more dense than liquids and sink (besides ice and water)

Question 13

How do particles behave in gaseous state?

Answer 13

Most mobile state that expands to fill its container

Question 14

How is the pressure of a gas determined

Answer 14

Collisions of gaseous particles with the walls of the container

Question 15

What are the assumptions of an IDEAL gas?

Answer 15

The pressure is not too high and temperature is not close to the condensation temperature

Question 16

What are the assumptions of the ideal gas Law?

Answer 16

1. Atoms/molecules of the gas have no volume
2. There are no attractive or repulsive forces acting between atoms or molecules of the gas (ping pong balls)

Question 17

Why is it assumed that gas volume is zero?

Answer 17

volume of atoms/molecules will be very small compared to the total volume of the container (at low pressure)

Question 18

Why is it assumed that there are no forces acting between the atoms or molecules of the gas?

Answer 18

Non-covalent interactions that normally would turn the gas into a liquid are taken to negligible if the temperature is greater vaporization/condensation

Question 19

What is BOYLE’S LAW?

Answer 19

At a constant temperature and fixed amount of gas, GAS VOLUME IS INVERSELY PROPORTIONAL TO GAS PRESSURE

Question 20

What equations are used in terms of Boyles Laws?

Answer 20

P1V1 = P2V2

Since PxV = constant

Question 21

What is CHARLES’S LAW?

Answer 21

At constant pressure and a fixed amount of gas, GAS VOLUME AND ABSOLUTE KELVIN TEMPERATURE IS DIRECTLY PROPORTIONAL

Question 22

What equations are used in Charles’s Law?

Answer 22

V1/T1 = V2/T2

Since V1/T1 = constant

Question 23

How does the equation appear when BOYLE’S and CHARLES’S LAWS are combined?

Answer 23

P1V1/T1 = P2V2/T2

Since PV/T = constant

For a fixed number of moles

Question 24

What is AVOGADRO’S LAW?

Answer 24

number of molecules of gas is directly proportional to gas volume

At fixed temperature and pressure

Question 25

What is the equation of Avogadro’s Law?

Answer 25

V1/n1 = V2/n2

Since V/n = constant

Question 26

What is the ideal gas law?

Answer 26

V = RnT/P

PV = nRT

Question 27

What is Avogadro’s Number?

Answer 27

of particles in one mole: 6.022 x 10^23

Question 28

How can Celsius be converted to Kelvin?

Answer 28

+ 273.15