20 Gases

Question 1

Boyle’s law

Answer 1

States that for a fixed mass of gas at constant temperature

pV = constant

Measurements plotted as a graph of pressure against 1 / volume gives a straight line through the origin

Question 2

Charles’ law

Answer 2

For a fixed mass of an ideal gas at constant pressure, its volume is directly proportional to its absolute temperature

V / T = constant

Work done = p 🔺v

Question 3

Isobaric change

Answer 3

Any change at constant pressure

Question 4

Isothermical

Answer 4

Any change at constant temperature

Question 5

Pressure law

Answer 5

For a fixed mass of ideal gas at constant volume, its pressure is directly proportional to its absolute temperature

P / T = constant

Question 6

Brownian motion

Answer 6

The random and unpredictable motion of a particle such as smoke particle caused by molecules of the surrounding substance colliding at random with the particle. Its discovery provided evidence for the existence of atoms

Question 7

Avogadro constant

Answer 7

The number of atoms in 12g of the carbon istope 12 carbon is defined as a mole. The value is 6.02 x10^23

Question 8

Pressure

Answer 8

Pressure of gas is the force per unit area that the gas exerts normally

Question 9

Molarity

Answer 9

number of moles of a certain quality of a substance

Question 10

ideal gas equation

Answer 10

Pv=nRT

Question 11

molar gas constant

Answer 11

8.31

Question 12

plot a graph of pV against T

Answer 12

line with the gradient = nR

Question 13

Boltzmann constant (k)

Answer 13

molar gas constant divded by the avogardo number

1.38*10-23

Question 14

Root mean square speed

Answer 14

square root of the mean value of the square of the molecular speeds.

Crms = [ C1^2 + C2^2 + Cn^2 / N ]^1/2

Question 15

kinetic theory equation

Answer 15

pV=1/3Nm(crms)^2

Question 16

mole

Answer 16

one mole of a substance consisting of identical particles is the quantity of substance that contains N particles of the substance

Question 17

molar mass

Answer 17

the mass of one mole of a substance

Question 18

ideal gas

Answer 18

a gas under conditions such that it obeys boyle’s law

Question 19

pressure law

Answer 19

for a fixed mass of an ideal gas at constant volume, its pressure is directly proportional to its absolute temperature

Question 20

kinetic energy

Answer 20

the energy of moving object due to its motion. for an object of mass m moving at speed v, it kinetic energy.

Ek = 1/2 mv^2

Question 21

kinetic energy of the molecules of an ideal gas

Answer 21

mean kinetic energy of a molecule of an ideal gas = 3/2KT

total kinetic energy of n moles of an ideal gas = 3/2 nRT

Question 22

kinetic theory of a gas

Answer 22

gas consists of identical point molecules which do not attract another
random motion
collided elastically

pV= 1/3 Nm (Crms)^2

Question 23

kinetic theory of gas equation

Answer 23

pV= 1/3 Nm (Crms)^2

Question 24

Pv = 1/3 Nmc^2

Answer 24

P= pressure on the side of the box
V = volume of the molecules in the box
N = number of particles in the box
M = mass of one particle
C^2 = mean square speed

Question 25

Random motion

Answer 25

When molecules are in a state of random motion they have a range of speeds and have no preferred direction of movement

Quality of a liquid and gas as described by kinetic energy

Question 26

State the assumptions used in the derivation pv= 1/3Nmc^2

Answer 26

Elastic collision
Intermolecular forces are negligible
Volume of molecules negligible
All molecules identical
Newtons laws of motion apply

Question 27

Describe how the motion of gas molecules can be used ti explain the pressure exerted by a gas on the walls of the container

Answer 27

Molecules are in constant random motion. When the molecules collide the walls exert a force on the molecules causing a change in momentum. The molecules exerts an force on the walls creating pressure

Question 28

what happens if the temperature of gas is increased

Answer 28

molecules move faster
root mean square increases
distribution curve becomes flatter and broader

Question 29

work done

Answer 29

pV

Question 30

average molecular kinetic energy

Answer 30

1/2 m(Crms)^2 = 3/2 KT = 3RT / 2N