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Question

2.Find the molar mass of the gas measured at the following specified conditions: 0.872 g occupying 1721 cm3 at 281 K and 1.85 atm.

Answer 1

A mole is defined as 6,023 x 10^23 molecules and occupies 22.4 L at STP (1 atm and 273 K). You can calculate this using the combined gas laws. PV/T=r. Calculate how many moles are present under those conditions (1.721L at 281K and 1.85 atm). Then divide grams by the moles to get the gram molecular weight. At STP, the volume would be 3.093L, which is 0.138 moles. Gram molecular weight = molar mass.