A balloon originally has 0.100 moles of helium and has a volume of 0.500 L. If 0.590 grams of He are added to the balloon, what will the new volume be, in L? (Assume temperature and pressure do not change.)

1.24 L

Explanation:

Avogadro's Law

Convert 0.590 g of He to moles.

0.590 g x (1 mol/4.00 g) = 0.1475 mol He

Add 0.1475 mol to 0.100 mol since the initial moles (n1) increases by this amount.

0.100 mol + 0.1475 mol = 0.2475 mol He

This will represent the final moles (n2)

The initial volume is given, 0.500 L. Plug in the values.