12th Practical Lesson: 1P13 Which can Dissolve More?

Yet another practical lesson and this time, the title of the practical was intriguing, thus we were quite excited to find out more. That day, when we entered the lab, I found that the class was less noisy than usual and I knew they wanted to know more about this practical. As a result, we could get started with this  practical lesson quickly. First, of course there were precautions for us to take and instructions for us to follow and we had to listen carefully to our Science teacher, Mr Low who was explaining some concepts first before starting us on the experiments.

What do we aim to achieve in this practical then? We hope to find out the solubility of different solutes differ in the same solvent. So some food for though before we start, controlling variables. We needed to know how to control variables to start with this experiment. So, controlling variables is to change only 1 variable at a time and keep the other variables constant to ensure a fair test. In this experiment, since we want to find out the solubility of different solutes, the factor or variables we must change is the type of solvent.

What about the other factors to be kept constant? They include:

1. Type of solvent
2. Mass of solute
3. Volume of solute
4. Temperature of solvent

The procedures we need to follow? Well, firstly, we had to measure 20cm³of water, then we had to weigh 1g of common salt using the electronic beam balance and add the common salt to the water. Next, we have to stir and dissolve the common salt in water. If it dissolves, completely, we have to weigh another 1g of salt and add it to the water. We have to continue adding the water until no more of such salt will dissolve anymore. We also have to repeat the following steps with baking soda and iodine crystals.

After the whole experiment, we had to tabulate our results in a table with the type of solute and the maximum amount of it dissolved/g.

So what can we conclude from the above results? We can conclude that of the 3 solutes tested, common salt is the most soluble in water and iodine crystals are the least soluble in water. Thus, different solutes have different solubility in the same solvent. How will I improve the experiment if I could? I will measure the solutes in smaller amounts so that I can get more accurate results.

The next practical lesson will be in the end of June as there are other activities on this day for the following weeks and I will miss the lab dearly. :D