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Gas lawsChemistryHigh schoolabout 0:53

How many moles of gas are in a 12 L container at 1.5 atm and 310 K?: animated lesson

A narrated, step-by-step gas laws video lesson with captions. Final answer: n = 0.707609 mol.

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Video with a synthetic English voice and captions. Pick another language for subtitles in that language, or open the interactive version.

Video narrated by a synthetic voice (Piper TTS, en_US-ljspeech-high voice (LJ Speech dataset, public domain)); the steps come from our maths engine and the answer was checked independently. Download MP4 (0.3 MB) · Captions (WebVTT)

Steps on screen

1. The problem
Worked example
How many moles of gas are in a 12 L container at 1.5 atm and 310 K?
2. Step by step
1. $R = 0.082057366\ \text{L·atm/(mol·K)}$
  Choose the gas constant to match the units
2. $n = \frac{PV}{RT} = \frac{1.5 \times 12}{0.082057366 \times 310} = 0.707609\ \text{mol}$
  Rearrange PV = nRT for n and substitute
3. The answer
$n = 0.707609\ \text{mol}$
n = 0.707609 mol
4. Check
- PV = 18 and nRT = 18, which agree.

Transcript

The problem. Here is the problem: How many moles of gas are in a 12 L container at 1.5 atm and 310 K? Solve PV equals nRT for n, with pressure in atm, volume in litres, amount in moles and temperature in kelvin.

Step by step. Choose the gas constant to match the units. Pressure is in atm and volume in litres. Rearrange PV equals nRT for n and substitute.

The answer. So the answer is n equals 0.707609 mol. 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.

Check. PV equals 18 and nRT equals 18, which agree.

About gas laws

Use the ideal gas law and the combined gas law to find pressure, volume, temperature or moles.

How many moles of gas are in a 12 L container at 1.5 atm…