Chem lab: Density & Chem lab: Elements &Compounds

This week, we did a lab on density. We used the same one formula to solve for the mass and the volume. We measured solid rectangular objects. We also measured the volume of liquids. We did another lab this week. It was the Element and Compounds. We broke down a compound into its elements and we formed a compound from two elements. The first part, we broke down the compound water into two elements hydrogen and oxygen. We mixed a universal indicator, a pinch of salt, and a half dish of water. We had to attach pencil lead to each of the two alligator clips on the 9-volt battery cap. We saw a reaction. The pencil lead on the black end made the solution turn purple; this element was oxygen. The pencil lead on the red end made the solution turn into a vanilla color; this was hydrogen. I saw bubbles at both ends of the lead, but I saw more bubbles at the red end. The balanced chemical reaction was 2 H2O ---> 2 H2 + O2 . For part 2, we formed a compound from two elements. In this part of the lab, we had to wear on goggles. We lit a candle and held a small piece of steel wool with crucible tongs into the flame of the candle. There was a cool chemical reaction. I saw yellow-orange sparks fly from the wool. The iron reacted with oxygen from the air. The sparks flew very quickly. There were silvery blue balls on the tips of the wool after it reacted. The name of the compound that formed from iron and oxygen was iron oxide, FeO. I liked this reaction better. There was more to see.