Students understand intuitively that, if one of two similar balloons is larger than the other, it contains more air. Avogadro's law enables students to analyze this quantitatively. The concept of the molar volume of a gas under standard conditions is a consequence of Avogadro's Law. This Powerpoint presentation introduces and explains the reasoning behind Avogadro's law. It also provides sample problems relating mass, volume, and the number of moles at STP.
Free worksheets for this topic are available on my website at http://www.evanschemistrycorner.com.