Question

If a 0.500 l sample of helium has a pressure of 170 mm hg and a temperature of 25.0 °c, how many moles of helium are present?

Answer 1

(aplus) 0.00457 mol

Answer 2

So I believe that you are going to be using the formula PV = nRT and you will be solving for moles. You have everything you need for this formula:
P = 170 mm hg **dont forget to change into atm
V = .500 L
R = gas constant (8.314 J / mol)
T = 25.0 C + 273 = temperature in Kelvin
Now it is just plug and chug
I hope this helped!
Have a fantastical day,
Em