# Example Concept-Based Lessons

Here is an idea to tie in the ideal gas equation with this concept. It also covers one of the new ‘Tools’ as an added bonus!

#### The Ideal Gas Equation and Tool 3: Mathematical Skills

Using units, symbols and numerical values

**1. Can you use the ideal gas equation, pV = nRT to derive the units for the gas constant, R?**

Hints:

1Pa = 1N

1Nm2 = 1J

Show your working below:

Answer:

pV = nRt

R = pV / nT

Substitute in units:

R = Pa m3 / mol K

R = Pa m3 mol -1 K-1 Substituting 1Pa = 1N

R = N m3 mol -1 K-1

Substituting 1 Nm3 = 1J

R = J mol-1 K-1

**2. This would then move into a lesson working out the experimental value of the gas content using cyclohexane.**

The limited instructions are deliberate. Students usually find it challenging to identify a value for the pressure – but it will be 100,000 Pa (approx.) when the plunger stops moving.

Measurements:

1. Mass of hypodermic needle empty

2. Mass of hypodermic needle with hexane

3. Start volume of 250cm3 gas syringe

4. Final volume of 250 cm3 gas syringe – take this when the volume stabilises

Hopefully, this illustrates that concept-based learning does not require any new skills in your teaching. It will require a slightly different mindset but with time, reflection, and experiment both you and your students will find it an enriching experience.

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