Question

A 2.5 L balloon is filled with helium to under constant pressure at a temperature of 25 °C. The temperature remains constant, but the balloon has a leak. What is the volume of helium in the balloon when the half of the helium has escaped?

I'm confused on this question. I used avogadro's law but I can't find moles

Answer 1

Hmmm, saw one like this earlier.
P V = n R T
assume the balloon fabric is so stretchy that it has no effect on pressure.
P is one atmosphere before and after
n at the end is 1/2 the original n
R is a constant
T is the same before and after
therefore if n is cut in half, only V can change with n
so
the final V is 1/2 the original V
(you do not need the n of mols, all you need to know is that it is one half of the starting n)

Answer 2

Is something missing here? The first sentence isn't complete. If you know the volume and pressure you can calculate moles from
2.5 L x (T/273) x (760/P) x 1/22.4 = ?

Answer 3

I need to use Avogadro's Law

Answer 4

P V = n R T
is
Avagadro's law
R is a constant that depends only on what units you are using so you can say
P1 V1 / (n1 T1) = P2 V2 /(n2 T2)

Answer 5

Try using your search engine, Google or whatever, for
Avogadro's Law