Why does the density of gas in a hot air balloon decrease as the gas is heated?

A. The mass of gas increases as temperature increases.
B. The volume of gas decreases as temperature increases.
C. The mass of gas decreases as temperature increases.
D. The volume of gas increases as temperature increases.

Question

Why does the density of gas in a hot air balloon decrease as the gas is heated?

 		A.	The mass of gas increases as temperature increases.
 		B.	The volume of gas decreases as temperature increases.
 		C.	The mass of gas decreases as temperature increases.
 		D.	The volume of gas increases as temperature increases.

michele_laino · Answer

the gas, receives heat so it expands itself, so the volume, occupied by the gas increases

michele_laino · Answer

more explanation: during heating, the kinetic energy of the molecules of the gas will increase, so the speed of each molecule will increase. Then the mean distance, travelled by each molecule of gas will increase

vera_ewing · Answer

So the answer is A? @Hoslos

michele_laino · Answer

I think D

vera_ewing · Answer

@Hoslos What is the answer?

anonymous · Answer

To start with, A and C are out, as mass never changes.

anonymous · Answer

When a gas is heated, the particles gain kinetic energy and the frequency of collision increases, thus increasing the pressure and conversely REDUCING the volume at a particular point at a given time. Hence, I would go for B.

vera_ewing · Answer

Hmm are you sure? I think it's D...

vera_ewing · Answer

Yeah it was D.