In this experiment, we will see three properties of ionic compounds: A. crystalline appearance B. solubility in water C electrical conductivity in water
Click 'Read More' to see the pictorial summary of what we will be doing on Friday.
Picture 1 shows to you the six ionic compounds we will be using in the lab session.
Picture 2 shows just how much salt you need to use. Do not exceed this amount.
Experiment A: In Picture 3, we see the crystalline nature of the ionic compounds. This is opposed to another appearance called 'amorphous'. 'Amorphous' or 'amorphous nature' is the same as the physical appearance of your powder at home.
Experiment B: Picture 4 shows to you when the salt is dissolved in water (left) or ethanol (right). It looks like the ionic compound may have dissolved in some of the ethanol - but this is theoretically wrong. Ionic compounds cannot dissolve in ethanol. Thus, how do we explain this?
This is the circuit setup that we will be using (Picture 5). Mr. A will be doing a demonstration so the whole class will just need to observe the procedure and note the observations.
Picture 6 shows the electrical measurement setup for all six ionic compounds in ethanol. Electrical conductivity for ions is because of their mobility; they can move throughout the solution so they can carry current. Because ionic compounds cannot even dissolve in ethanol, we expect the electrical conductivity to be ____. Therefore, the bulb does not light up.
Picture 7 shows the electrical measurement setup for all six ionic compounds in water. By right, ionic compounds dissolve in water, so the bulb should be lit. However, we see that the bulbs are not lit/ barely lit. Why is this so?