ideal gases

Question 1

The mole

Answer 1

one mole of any substance is the amount of that substance which contains the same number of particles as 12g of carbon 12.
1 mol= NA = 6.02 x 10^23 particles/atoms / molecules (Avogadro constant)

Question 2

The gas laws

Answer 2

the gas laws describe the experimental evidence about the ways pressure, vol and temp are related.

Question 3

Boyle’s law

Answer 3

p1V1 = p2V2 ; T= constant
For a given fixed mass of gas at constant temperature the pressure of the gas varies inversely proportional to its volume provided all other physical conditions remain unchanged.
p α 1/v ; pV= constant

Question 4

Charles’s law

Answer 4

V1/T1 = V2T2 ; p = constant
For a given fixed mass of a gas at pressure the volume varies proportional to its absolute temperature given that all physical conditions remain the same.
V α T

Question 5

gay lussac’s law

Answer 5

p α T p1 / T1 = p2 / T2
for a given fixed mass of gas at constant volume the pressure is proportional to its absolute temperature given that all physical conditions remain the same.

Question 6

kelvin to celsius

Answer 6

T(K) = T(C) + 273.15

Question 7

Ideal gas

Answer 7

A gas obeying pV α T , where T is the thermodynamic temp is known as an ideal gas.

Question 8

Equation of state of an ideal gas or the ideal gas law or universal gas eq

Answer 8

pV = nRT
an ideal gas is a gas that obeys the eq pV= nRT
p = pressure of gas (Pa)
V= vol of gas(m^3)
n= num of moles of the gas (mol)
R=universal molar gas constant (8.31/mol.k)
T= absolute temp of the gas (K)

Question 9

real gases do not follow pV= nrt at

Answer 9

1) high pressure
2) when the gas is near the liquefaction point

Question 10

pv = nkT

Answer 10

must learn derivation

Question 11

kinetic theory

Answer 11

The analysis of matter in terms of atoms in random continuous motion is called the kinetic theory.

Question 12

The kinetic theory is based on assumption :

Answer 12

1) A gas consists of large num of molecules behaving as hard identical spheres.
2) The gas molecules are constantly in free rapid motion.
3) Gas molecules collide elastically with one another and the walls of the container.
4) There are no intermolecular forces except during collision.
5) The total volume of the gas molecules is negligible compared to the volume of the container which is also the volume of the gas.
6) The duration of the collisions is negligible compared to the time interval between collisions.
7) The diameter of the molecule is negligible compared to the avg intermolecular distance.

Question 13

force on wall exerted by 1 molecule

Answer 13

F = ▲p / ▲t
= 2mu x (mu/L)
= mu^2 / L

Question 14

force due to N such molecules

Answer 14

F = m/L [u1^2 + u2^2 +… + uN^2]

Question 15

pressure exerted

Answer 15

F = m/L [u1^2 + u2^2 +… + uN^2]
P = F/A = F/L^2
F = m/L^3 [u1^2 + u2^2 +… + uN^2]
= m/L^3 [u1^2 + u2^2 +… + uN^2]
= m/v [u1^2 + u2^2 +… + uN^2]