A 1.50mol sample of helium at a certain temperature and pressure has a volume of 31.4L. A second sample of helium at the same temp and pressure has a volume of 42.2L. How many moles of Helium are in the second sample?

To find out how many moles of helium are in the second sample, we can use the relationship between moles, volume, and the ideal gas law equation, which states:

PV = nRT

Where:
P is the pressure
V is the volume
n is the number of moles
R is the ideal gas constant (0.0821 L·atm/(mol·K))
T is the temperature measured in Kelvin

In this case, we have the same temperature and pressure for both samples, so we can treat them as the same system.

We can set up a ratio of the volumes to find the ratio of moles:

(Volume 2 / Volume 1) = (moles 2 / moles 1)

Plugging in the given values:

(42.2 L / 31.4 L) = (moles 2 / 1.50 mol)

Now we can solve for moles 2:

moles 2 = (42.2 L / 31.4 L) * 1.50 mol

moles 2 ≈ 2.02 mol

Therefore, there are approximately 2.02 moles of helium in the second sample.

well, PV=nRT so

V/n=RT/P so if RT/P remains constant

V1/n1=V2/n2

and you are solving for n2.