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.