WEBVTT

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Here is the problem: How many moles of gas are in a 30 L container at 0.5 atm and 280 K?

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Solve PV equals nRT for n, with pressure in atm, volume in litres, amount in moles and temperature in kelvin.

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Choose the gas constant to match the units. Pressure is in atm and volume in litres.

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Rearrange PV equals nRT for n and substitute.

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So the answer is n equals 0.652853 mol.

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An ideal gas obeys PV equals nRT: pressure times volume is proportional to the amount of gas and its absolute temperature. Real gases follow it closely at low pressure and high temperature.

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PV equals 15 and nRT equals 15, which agree.