1. Aqueous solutions of ionic compounds (also known as “salts”) take on the color of the solid solute. Observe the sample solutions on the front bench and notice that each solution matches the color of the solute.
The only apparent exception is that “white” salts don’t give white solutions, they give “colorless” ones. That’s because the crystals are actually colorless, but all the light traveling through them mixes and diffracts and interferes and blends to produce white. A huge crystal of table salt is actually transparent (there’s one at the Smithsonian Institution that’s a couple of feet tall, and it’s amazing).
What color are the crystals of sodium nitrate? What is it’s formula?
2. Obtain a small test tube, and fill it approximately ½ way with lead (II) nitrate solution. What is the formula for lead (II) nitrate? What color do you expect it's crystals to be?
3. Obtain another small test tube, and put a tiny scoop of sodium iodide powder in it. What color is solid sodium iodide? What is it’s formula?
4. Add water to the sodium iodide until the test tube is about ½ full. What color is the solution?
5. Pour both solutions into a larger test tube. What happens?
6. Write the skeleton equation for the reaction that just occurred. You will need to figure out the formulas of the products.
7. Write the complete balanced equation for the reaction that just occurred.
8. Which compound in #7 was the visible one? Explain how you could tell.
9. Dispose of the solutions according to your teacher. DO NOT put them down the drain!
10. What type of reaction was this? (Synthesis, etc)
[MHS Chemistry page]