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This question was answered but the answer was not legible I could not understand.

This is all one question with different parts.

(2a) Use the kinetic molecular theory to explain why volume and pressur and inversly related.

(2b) One mole of Kr and one mole of N2 are placed in seperate flasks having the same volume and temperature. Using the KMT, (i) Compare the pressure of the gases in their containers; (ii) compare the rms velocities; and (iii) compare the kinetic energies of the gases.

(2c) Determine the molar mass of a gas with density 1.588 g/L at 80.00 degrees Celcius and 745 torr pressure.

Explanation / Answer

2a)

pressure isnothing but force exerted by gas on walls of container.

P=F/A

if you increasethe volume,you are increasing the surface area of sides.

since area increases , P will decrease.

Sopressure and volume are inversely related.

It is also calledBoyle's law.

P*V= constant

2b)

i)

P*V=n*R*T

when V,n and T are same, P will be same for both

Pressure of gases is same in both container.

ii)

Vrms = sqrt(3*R*T/M)

Since R and T is same for both gases,

Vrms(Kr)/ Vrms(N2) =sqrt (M(N2) / M(Kr))

                          =sqrt (28/84)

                         =0.58

iii)

K.E = 0.5*m*v^2

K.E(Kr)/K.E(N2) = M(Kr)/M(N2) * Vrms(Kr)/ Vrms(N2) = 84/28 * (0.58)^2 =1

So kinetic enrgy of both gases will equal

2c)

P= 745 torr = 745/760 atm =0.98 atm

density,d = 1.588 g/L

T = 80 oC =(80+273) K =353 K

Use:

P*V=n*R*T

P*V=(maas/ molarmas)*R*T

P*molar mass=(maas/ V)*R*T

P*molar mass=(density)*R*T

putting values,

0.98*molarmass = 1.588*0.0821*353

molarmass   = 47gm

Answer: 47 gm

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