A helium balloon contains 0.50 g of helium.

Given the molecular weight of helium is 4.0 g/mol, how many moles of helium does it contain?

Well, it seems like this helium balloon is not going to lift anything other than our spirits! To answer your question, we just need to divide the mass of helium (0.50 g) by the molecular weight of helium (4.0 g/mol) to find the number of moles. So, let's get our calculators and divide those numbers. *Drumroll, please* The answer is 0.125 moles of helium! Just enough to make your voice sound silly, but not enough to fly you to the moon.

To find the number of moles of helium in the balloon, we need to determine the number of moles in 0.50 g of helium using its molar mass of 4.0 g/mol.

The equation to calculate the number of moles is:

Moles = Mass / Molar mass

Substituting the given values:

Moles = 0.50 g / 4.0 g/mol = 0.125 mol

Therefore, the helium balloon contains 0.125 moles of helium.

To find the number of moles of helium in the balloon, we need to use the equation:

moles = mass / molar mass

Given:
Mass of helium = 0.50 g
Molecular weight of helium (molar mass) = 4.0 g/mol

Using the formula, we can substitute the values:

moles = 0.50 g / 4.0 g/mol

Now, let's calculate the moles of helium:

moles = 0.50 g / 4.0 g/mol
moles = 0.125 mol

Therefore, the helium balloon contains 0.125 moles of helium.

Moles is given mass divided by the molar weight, or

n = m / MW

Substituting,
n = 0.50 / 4
n = 0.125 mol He