1 ) How many moles of He are in 17 g of He? 2 ) A flight attendant wants to chan
ID: 2010458 • Letter: 1
Question
1 ) How many moles of He are in 17 g of He?2 ) A flight attendant wants to change the temperature of the air in the cabin from 18.0° C to 21.2° C without changing the number of moles of air per m3. What fractional change in pressure would be required?
3 ) A cylinder in a car engine takes Vi = 4.50 10-2 m3 of air into the chamber at 30° C and at atmospheric pressure. The piston then compresses the air to 0.123 times of the original volume (0.123 Vi) and to 24.9 times the original pressure (24.9 Pi). What is the new temperature of the air?
Explanation / Answer
number of moles of He=wt of He gas/molecular weight of helium =17gms/4gms/mole=4.25moles 2)we know that the absolute temperature T is directly proportional to the pressure when the volume of the gas and the number ofd moles of gas are unaltered according to charles law here in this situation we have volume of the gas and the number of moles of gas as constant hence we can apply this law TP fractional change in pressure=(18+273)/(21.2+273)=0.9891 we added 273 because the temperature should be in absolute scale 3)PV/T should be constant where T is in absolute scale P1=1atm V1=v T1=293K T2=? P2=24.9atm V2=0.123v T2=897.3K=624C
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.