**States of Matter Quiz-3**

**States of Matter Quiz-3**

**Dear Readers,**

**The one subject in NEET which is candidates who can easily attain good marks is Chemistry. That's the reason, often, one doesn’t pay notice and choose to compromise it. But if one wants to rank above others, the tip is to be thorough with NEET chemistry concepts. The understanding of reactions and definite basic understanding is what requires major attention in Chemistry but once done it only gets simpler from there. The main focus on the to-do list should be on getting a hang of the NCERT syllabus of NEET chemistry..**

**Q1.**The rate of diffusion of methane at a given temperature is twice that of gas X. The molecular mass of gas X is

Solution

(a) Let the rate of diffusion of gas x=a and molecular mass =M So, r

(a) Let the rate of diffusion of gas x=a and molecular mass =M So, r

_{x}=a,M_{x}=M r_{CH4}=2a,M_{CH4}=16 r_{x}/r_{CH4}=√(M_{CH4}/M_{x}) or a/2a=√(16/M_{x}) or M_{x}=64**Q2.**The molecular weight of O

_{2}and SO

_{2}are 32 and 64 respectively. If one litre of O

_{2}at 15℃ and 759 mm pressure contains N molecules, the number of molecules in two litre of SO

_{2}under the same conditions of temperature and pressure will be:

Solution

(c)
V∝ mole at same P and T.

**Q3.**Surface tension of water is 73 dyne cm

^{-1}at 20℃. If surface area is increased by 0.10 m

^{2}, work done is

Solution

(b) Work done = surface tension × increase in area =73×0.10=73×0.10×10

(b) Work done = surface tension × increase in area =73×0.10=73×0.10×10

^{4}=7.3×10^{4}erg

**Q4.**The rms speed of N

_{2}molecules in a gas is u. If the temperature is doubled and the nitrogen molecules dissociate into nitrogen atoms, the rms speed becomes

Solution

(b) u

(b) u

_{1}/u_{2}=√((n_{1}T_{1})/(n_{2}T_{2}))=√((n×T)/(2n×2T))=√(1/4 )=1/2 ∴ u_{2}=2u_{1}**Q5.**Equal masses of ethane and hydrogen are mixed in an empty container at 25℃. The fraction of the total pressure exerted by hydrogen is

Solution

(d) Moles of H

(d) Moles of H

_{2}=w/2, and ethane =w/30 Total mo. of moles =w/2+w/30=16w/30 Partial pressure of H_{2}=p×(w/2)/(16w/30) =w/2×30/16w=30/32=15/16**Q6.**Which is a postulate of kinetic theory of gases?

Solution

(c) Follow assumptions of kinetic theory.

(c) Follow assumptions of kinetic theory.

**Q7.**For 1 mole of gas, the average kinetic energy is given as E. The u

_{rms}of gas is:

Solution

(a)
Average kinetic energy,E=3/2 RT
u

_{rms}=√(3RT/M)=√(2E/M)**Q8.**The number of collisions depends on:

Solution

(d) Collision frequency =u

(d) Collision frequency =u

_{rms}/Î»;u_{rms}depends on T,Î» depends on P and T.**Q9.**Which of the following statement is not true?

Solution

(c)
According to Graham’s law the rate of diffusion is inversely proportional to square root of molecular weight and density.
r∝1/√d and r∝1/√M

**Q10.**The edge of unit cell of fcc Xe crystal is 620 pm. The radius of Xe atom is

Solution

(c)
r=a/(2√2)=620/(2√2)=219.25 pm