 # A glass tube of volume 112ml,containing a gas is partially evacuated till the pressure in it drops to 3.8*10-5 torr at 00C.the number of molecules of the gas remaining in the tube is?

14 years ago

volume = 0.112 L

pressure = 3.75 atm

temp = 273K

gas law is PV=nRT

n=3.75*0.112/(0.0821*273)

n=0.01874 moles

A mole has 6.0221415×1023 atoms or molecules of the pure substance being measured

no. of molecules = 112.87x1020

--

regards

Ramesh Badiuddin askIITians.ismu Expert
148 Points
14 years ago

HI sameer ali

V=112 ml

P = 3.8*10-5 torr

T=00C=273 k

Use the formula PV=nRT

here n number of mole

and R is gas constant

and find the value of n

and we know that 1 mole of gas contain 1 avagadro number(A) of molecules

so n mole of contain n*A number of molecule at 00C

Take care of units during calculation

Please feel free to post as many doubts on our discussion forum as you can. If you find any question Difficult to understand - post it here and we will get you the answer and detailed solution very quickly.

All the best sameer ali

Regards,