The Chemistry IAA experiment is a big complicated which is why it is explained in this article very clearly. The IAA investigates the properties covalent substances have, in this case, we will be using urea, glucose and salol as the covalent substance. As this IAA exam is 10% of a GCSE in science, it is extremely important to master this exam.
Firstly, let’s identify what the independent and dependant variables are:
Independent Variable – Number of carbon atoms
Dependant Variable – Melting point of substance
Independent variable causes a change in Dependent Variable and it isn’t possible that Dependent Variable could cause a change in Independent Variable. So, the number of carbon atoms causes a change in the melting point.
- Graphite rods x2
- Wires x4
- Crocodile clips x2
- 1 set of batteries
|The circuit required in this experiment|
Using distilled water as normal water has potassium and magnesium in it which makes it conduct electricity
(this is where you should use your results and scientific knowledge)
Ultimately, urea, glucose and salol didn’t conduct as a solid neither as a liquid. However, we found that the melting point of salol was 41.5 degrees. This shows that covalent bonds don’t conduct electricity. This is because covalent substance (with exception to graphite) share electrons between atoms and therefore don’t have free electrons. This makes the substances not have a flow of electrons therefore charge.