Calculating Mass of Helium Gas at STP

[kasse]

[SOLVED] Mass of gas

Homework Statement

What mass of He gas occupies 8.5 L at 273 K and 1 atm?

Homework Equations

PV = nRT

The Attempt at a Solution

n = PV/RT = (101 kPa * 8.5 L)/(8.3145 * 273 K) = 2.64E-3 mol --> 10.6 g

My solutions manual says 1.52 g. Am I right or wrong?

 

[Dick]

2.64E-3 mole? Really? I seem to remember a mole of gas at STP is 22.4 liters. What does a mole of helium mass? The book is right.