Test: JEE Previous Year Questions- States of Matter - JEE MCQ

According to kinetic theory the gas molecules are in a state of constant rapid motion in all possible directions colloiding in a random manner with one another and with the walls of the container and between two successive collisions molecules travel in a straight line path but show haphazard motion due to collisions.

Average kinetic energy ∝ Temperature in Kelvin

(KE40) / (KE20) = (3/2 nR * 313)/(3/2 nR*293)

KE40 / KE20 = T2/T1 = 40 + 273 / 20 + 273  = 313/293

The correct answer is Option C.

In van der Waals equation of state of the gas law, the constant b is a measure of the volume occupied by the molecules. 
 
It gives the effective size of the gas molecules. The greater value of b indicates a larger size of the molecules and smaller compressible volume.

Most probable velocity increase and fraction of molecule possessing most probable velocity decrease.

Let the mass of methane and oxygen be m gm.
Mole fraction of oxygen, x_O2 = m/32/(m/32 +m/16) = 1/3
Let the total pressure be P.
Partial pressure of O₂, p_O2 = P × x_O2 = P x 1/3 = P/3

Number of moles per litre can be represented as n/V so if we shift RT to the left side and V to the right side then we can get n/V that is our number of moles per litre is equal to p/RT and so option a is correct.

The different values of R are as follow:-
8.314 J mol^-1 K^-1, 8.314×107 erg mol^-1 K^-1, 0.0821 atm-lit mol-1 K^-1 or 2 cal mol^-1 K^-1

The volume occupied by water molecules in vapour phase is (1×10⁻⁴) dm³, that is approximately (1×10⁻³) m³.
pvapV = nH₂O mol
3170 × 1 × 10⁻³ = nH2O × 8.314 × 300K
nH₂O = 3170 × 1 × 10⁻³ / 8.314 × 300
= 1.27 × 10⁻³ mol

a and b are the van der Waals constant for gases where ‘a’ means the force of attraction while ‘b’ is the effective size of the molecule. Chlorine is more easily liquefied than Ethane so ‘a’  of chlorine will must be greater than a value of Ethane. Also, Chlorine is more easily liquefied then the ‘b’ of chlorine should be less than ‘b’ of Ethane. For smaller size we have more attraction and so the liquefaction will be easy.

The correct answer is option A
Rate of diffusion: r     α    p



r_A/r_B = p_A/p_B.(M_B/M_A)^1/2
Hence, p_Bp_A (M_B/M_A)^1/2 is the answer.

The average kinetic energy of a gas particle is directly proportional to the temperature. An increase in temperature increases the speed in which the gas molecules move. All gases at a given temperature have the same average kinetic energy. Lighter gas molecules move faster than heavier molecules.

General equation for combustion of hydrocarbon:
CxHy + (x+ y/4)O₂ → xCO₂ + (y/2)H₂O
Number of moles of CO2 produced = 3.08/44 = 0.07
Number of moles of H₂O produced = 0.72/18 = 0.04
SO, x / (y/2) = 0.07/0.04 =  7/4
The formula of hydrocarbon is C₇H₈