Lab Report Phys And Chem Changes

Billy Foshay Drew Jacobs Period 6 Dr. Debona Observing Physical & Chemical Changes 1.

Before heating a piece of copper wire in a bunsen burner flame, we observed

characteristics of the copper that would help us decide whether the substance underwent a physical or a chemical change. We noticed that the copper was an orangy color, 3 cm in length, that it was ductile, had a smooth texture and a point tip. When we held the copper over the bunsen burner flame, the copper turned a bright orange while it was burning. Toward the end the copper began to melt and came close to dripping. After taking the copper out of the fire and letting cool for a short amount of time, the copper was very bendable. We also noticed that a small ball had formed at the top where the copper began to melt. Immediately after we took it out of the flame, the color of the copper was a blackish blue, but after letting it sit for a while the color turned back to more of an orange. These observations led us to believe that the copper underwent a physical change and not a chemical change. We were led to believe it was physical because there were no signs of gas, permeant color changes, or smell that would be signs of a chemical change. 2.

The magnesium ribbon that was to be heated in the bunsen burner flame was silver,

bendable, light, and brittle. When the magnesium ribbon was put into the flame, within 3 seconds the ribbon glowed intensely bright white. There was a gas realized from the reaction. After being removed from the heat, the ribbon fell apart into little pieces of a white ash-like substance. After cooled, what was left of the magnesium ribbon if touched would break down into a white powder. These observations led us to believe that the magnesium ribbon underwent a chemical change. The bright white flashing, the release of a gas, and complete transformation from

magnesium ribbon to a white powder are all signs that the ribbon underwent a chemical change when heated in the bunsen burner. 3.

When we put the aluminum metal into a copper chloride solution we observed a chemical

reaction. After the aluminum was placed in the solution the contents of the beaker turned orange/red. The solution began to fizz, and there was a gas released that smelled like smoke. From touching the beaker we were able to feel that the beaker was very hot when the aluminum and chloride solution were reacting. At the end we observed that there was a dark broken up powder sitting at the bottom of the beaker. The aluminum underwent a chemical change because gas, color change, and a release of heat are all ways to tell if a chemical reaction is occurring. 4.

While treating the magnesium metal with dilute hydrochloric acid we observed a

chemical change to the magnesium. It is evident from what we observed. First we saw the metal foam, and turn white. There was also a faint gassy smell that came off the reaction, and the beaker got hot. After it the reaction was finished we realized there was no magnesium left. From this we drew the conclusion that the magnesium was disintegrated. We can tell this was a chemical change because there were signs of a chemical change such as the faint gas, and reaction releasing heat. 5.

For trying to find the the density of a penny, we used two methods. One is cm cubed

which involves using a ruler to measure the length width and height and finding the mass with an electronic scale. The other method is ml in which we used a graduated cylinder to measure the displacement of the water after we put the pennies in. When we used the cm cubed method we calculated a density of the penny to be