Chemistry Lab Chemical and Physical Properties
Did you observe any chemical changes in this experiment? Yes there were a lot of chemical changes with the HCl, one with the NaOH, and some with heat and hot water. B. What evidence did you use to decide that something was a chemical change? The starting and ending product were different, color change, sound, heat, and gas production. C. Give at least two examples of chemical changes you observed: HCl and CuCO3 turned bright green, NaOH and CuCO3 D. Classify the following properties of sodium metal as physical or chemical: * Silver metallic color: chemical * Turns gray in air: chemical * Melts at 98*C: physical * Reacts explosively with chlorine gas: chemical E.
Classify the following changes as physical or chemical : * Water freezes at O*C: physical * Baking soda when combined with vinegar produces bubbles: chemical * Mothballs gradually disappear at room temperature: chemical * Ice cubes in freezer get smaller with time: chemical * Baking soda loses mass as its heated: chemical * Tarnishing of silver: chemical F. How would you show that dissolving table salt is a physical change? When you dissolve salt it is a chemical change because it dissociates in Na+ ions and Cl- ions. But when you remove the water then the salt remains which is physical change. (http://chemistry. about. com/od/matter/a/lsdissolving-salt-in-water-a-chemical-change-orphysical-change. htm )