Observing Changes – Lab

Purpose:
To observe and discover properties of chemical and physical properties of water, copper sulfate powder, iron (wool), sodium carbonate, hydrochloric acid, and magnesium and how they react with one another. Hypothesis:

We can recognize physical and chemical changes from the way substances react with one another. It’s a physical change when its size, shape, state, solution changes and it’s often easy to reverse. Chemical changes is when there is a change of color, precipitate forming, heat or light being given off, or change in odor and it’s often hard to reverse. Observations:

Part 1: Copper (II) Sulfate and Water
Properties of water Clear, odorless, tasteless, and is a liquid. Properties of copper (II) sulfate Blue, powder, and is a solid. After we put some copper (II) sulfate in the test tube followed by 4cm of water the water turned kind of blue, then when we put the cap on the test tube and shook it, the copper sulfate dissolved in the water and it turned bluer. I also observed that after shaking there were still pieces of the copper sulfate at the bottom of the test tube. This change was a physical change because there was a change in color (chemical) and a change if form (physical). I would argue that this is a physical change because you could easily get some of the copper (II) sulfate back by heating it up and let the water evaporate, also no new substance was found when mixing those two substances together. Although the color changed it’s still reversible. Part 2: Copper (II) Sulfate Mixture and Iron (wool)

Properties of Copper (II) Sulfate and Water Blue, and is a liquid. Properties of Iron (steel-wool) wire-like, grayish, fluffy, looks like hair ball, and is a solid. After we gently placed the iron (steel-wool) in the copper (II) sulfate and water mixture nothing happened. After a few minutes the wool lost its color and turned red, it just settled at the bottom of the test tube. The piece of iron was not the only thing that lost its color, the copper (II) sulfate and water mixture also lost its color it turned yellowish-greenish instead of blue, it looked like it displaced the copper to make copper metal, and the color of the liquid changed probably because the color of the steel wool mixed with the blue liquid to create a disgusting yellowish green color. This is a chemical change because the liquid and the steel wool both changed color. Also, the steel iron changed from that to some sort of copper metal. In addition if it’s possible to reverse it would be highly difficult. Part 3: Copper (II) Sulfate and Sodium Carbonate

Properties of remainder of Copper (II) Sulfate and Water Blue, and is a liquid. Properties of Sodium Carbonate clear and is a liquid.
When we put the sodium carbonate in the rest of the blue liquid solution and shook it, it turned into a lighter blue color but also looked very thick, cloudy, and stills a liquid. There were some remains along the glass of the test tube. I also observed that you can’t see through the blue liquid now because it’s thicker. This is a chemical change because a new substance was created, the color changed, it became thicker and it’s highly difficult to separate the two substances from one another. Therefore it is considered to be a chemical change. Part 4: Hydrochloric Acid and Magnesium

Properties of Hydrochloric Acid clear and is a liquid.
Properties of Magnesium silver, light, shiny, bendable and is a solid. When we had the acid in the test tube and added the magnesium the acid started fizzing and bubbles were coming out of the magnesium. I also saw that the magnesium sunk to the bottom. The magnesium lost its color a bit and black parts of the magnesium were floating around in the acid. Also the acid turned cloudy. After a couple of minutes there was steam at the top of the test tube and the test tube got warmer, there was also vapor along the inside of the glass (top). The bottom of the test tube was clear, but the top was cloudy. The magnesium continued to make bubbles and fizz, the bubbles were moving upward and some stuck to the top and side of the class, it looks like Sprite. It was fizzing for a long time, but I think by the time it finishes there would be nothing left of the magnesium. This is a chemical change because a hydrogen gas was released and fizzing occurred. The magnesium ribbon would dissolve in the acid and it would be really difficult to get it back. Therefore this is a chemical change it is nearly impossible to reverse. Conclusion:

My hypothesis for figuring out how we can recognize physical and chemical change was correct. 14. a) There were many changes, like color change, form change, heat being given off, and fizzing. This supports my hypothesis because the changes to the substances that I observed helped me figure out if the change is physical or chemical. b) Part 1 state change from solid to liquid.

Part 2 none.
Part 3 thickness.
Part 4 none.
c) The clues we observed were:
– A new color appeared
– Bubbles of gas are formed
– Heat or light given off
– The change is difficult to reverse
d) Changes that might be reversed is from when the copper (II) sulfate dissolved in the water by heating it and letting the water evaporate, then you can cool the copper sulfate down and make it a powder. Another way to resolve a change is the thickness change simply by adding water.