With the Massing Gases: Avogadro’s Law Demonstration—ChemTopic™ Lab Activity, use Avogadro’s law determine the molar mass of several gases. Measure the masses of equal volumes of gases trapped inside syringes, and compare their mass ratios to calculate the molar mass. Available as part of The Gas Laws—ChemTopic™ Labs digital collection. Click the Price link for digital collection pricing.