Endothermic and Exothermic Reactions

November 13, 2008 Endothermic and Exothermic Reactions Day 1, Prd 4

Purpose: To investigate heal transfer in reaction

***Please refer to the hand-out given before the lab for the procedure and the materials used.








　
　
　
　
　

Observations:

Reaction 1:

When calcium chloride and phenolphthalein touched the water and when they were shook together, they were bubbles forming and along with them was a fizzing sound. Also, as the ziploc bag was shook and as the time passed, the bag felt hot and there was this smell. It smelled like burning plastic to me. Furthermore, as minutes passed, the calcium chloride and phenolphthalein mixture caught a pink tink and eventually, the contents of the ziploc bag turned pink.

Reaction 2:

There was a fizzing sound, big bubbles - bigger than the bubbles in the first reaction. The ziploc bag felt cold and its contents turned whitish when the bubbles were forming and turned cloudy when the bubbles from the reaction disappeared. The ziploc bag was also inflating as the bubbles were forming.

The burning splint lost its light when inserted in the bag. Our hypothesis is that the gas created was carbon dioxide because CO2 turns the flames off.

Reaction 3:

There were bubbles, and a fizzing sound. The reacton was odorless but it had colour. After the reaction, some bubbles stayed on the surface of the Ziploc bag. The liquid in the Ziploc bag was white and as the reaction passed, the colour of the liquid went from white to transparent.

Conclusion:

I learned that bubbles can affect the colour of the liquid. Also, water, when added to compunds, form bubbles.

Lab 9: The Synthesis and Detection of Copper

November 6, 2008 The Synthesis and Detection of Copper Julie Anne A. Day 1, Prd 4

Purpose: To transform copper (II) chloride into pure copper metal.

Materials:
-copper (II) chloride
-two medium-sized beakers
-aluminum foil
-crucible tongs
-waste container
-water
-bunsen burner


Procedure:
1. Pour 30 mL copper (II) chloride solution in the beaker.
2. Roll the aluminum foil and place it in the copper (II) chloride solution. Observe.
3. After 5 minutes, pick out the larger chunk of the aluminum foil with crucible tongs.
4. Put the solution to the waste container except for the copper at the bottom of it.
5. Put water on the copper and shake the beaker a bit.
6. Pour the water on the waste container. Then, take a piece of copper.
7. Light the Bunsen burner on to a roaring flame.
8. Do the flame test colour and burn the "made" copper. If the flame, turns green, you've made copper and your experiment is successful!

Data and Observations:

1. Copper (II) Chloride --- CuCl2

BEFORE:
It's a blue green, transparent-ish, thin liquid and it's not very viscous.
AFTER:
The same descriptions but it contained bits of black things which came off of the aluminum.
OBSERVATIONS:
Little bubbles formed when aluminum was submerged to the solution. The bubbles had an upward motion.


2. Aluminum Foil

BEFORE:
It's very shiny, smooth, metallic, easy to crumple and tear, odourless, noisy, and it seems to be ductile.
AFTER:
The part that was soaked with CuCl2 became soggy. Also, it sort of decreased in size. Furthermore, black things formed on it like barnacles on a boat. These black things increase in size and changed colour - from black to orangish brown. Also, these things looked powdery, as if they were fine grains. Finally, they fell off when the aluminum foil is shook.
OBSERVATIONS:
Bubbles formed on it and as the time passes, the bubbles became bigger and eventually, the black things formed.

3. The "Made" Copper
The copper looked soggy because it was saturated. Before it reached its orangish brownish colour, it started as black things on the aluminum foil. These black things were like barnacles on a boat when they formed on the aluminum foil. Then, they changed colour as 5 mins gone by. When the aluminum was shook, the copper fell off. When my lab partner and I burnt the copper, the flame turned green which meant we had a successful experiment.

Questions:

1. How can copper be extracted from a compound of copper, purified, and then tested to verify success.

Copper can be extracted from a compound of copper by saturating aluminum foil to that compound. The aluminum sucks the copper from the compound, copper (II) chloride, and this copper sticks to the aluminum. Another hypothesis could be that the aluminum turned to copper because as observed from the experiment, the aluminum became soggy; its pieces shortened in size; and some of the aluminum foil fell off after being saturated with copper (II) chloride.

In the BC Science 9 Book, on pg. 81, the copper was purified by putting hydrochloric acid to it. In our experiment, however, we used water because it worked as well as hydrochloric acid.

We tested the outcome of the experiment by burning it and referring to the flame test colour that we did in the earlier labs. (Basically, by flame testing.) If the flame turns green in a roaring flame, which it did for our experiment, copper is present.

Conclusion:
I learned that you can make copper just by adding/saturating aluminum foil in copper (II) chloride. I also realized that chemistry teachers may benefit from this reaction because they can use this copper made from this reaction for not-so special labs. By doing so, they don't need to buy copper for a not-so-special experiments.

Lab 8: The Synthesis of Oxygen

October 31, 2008 The Synthesis of Oxygen Julie Anne A. Day 1, Prd 4

Purpose: To observe what happens to the glowing splint when it's placed in a test tube with oxygen.

Materials:
-glowing splint
-candle
-H2O2---Hydrogen Peroxide
-KI----potassium iodide
-test tube
-dishwashing liquid

Procedure:
1. Put the catalyst for the experiment in the hydrogen peroxide which is in the test tube.
2. Then, light the splint and wave it in the air so that you'll get a glowing splint.
3. Insert the glowing splint inside the test tube where the catalyst and the hydrogen peroxide are. Don't let the splint touch the test tube contents.
4. Observe what happens.
5. Then, put in a drop of dishwashing liquid.
6. Observe.
7. Insert another glowing splint in the test tube.

Data and Observations:

1. Hydrogen Peroxide
-Before:
it was an odourless, clear liquid.
-After:
when the catalyst was added to it, it turned yellow and there were bubbles forming, too.

2. Catalyst
-Before:
the look rocky
-After:
they sunk to the bottom and i didn't see a lot of them at the bottom of the test tube.


Dishwashing Liquid
-Before:
an orange, very viscous liquid, with a soapy odor. It was really hard to manage it because of its viscosity.
-After:
it created big bubbles in the potassium iodide. Also, it's strong colour didn't affect the colour of the compound.


Glowing Splint
-Before:
it was glowing and a little bit burnt on the sides of the glowing part.
-After:
when it was put in the oxygen-filled test tube, it relit.

***Also, when the dishwashing liquid was combined with KI, the compound formed when the catalyst and H2O2 was combined, the compound in the test tube started to overflow. However, the only thing that overflowed were the bubbles, not the liquid.

Questions:

1. What happens to a glowing splint when it is placed in pure oxygen?

The glowing splint relights when it is placed in oxygen.

2. If you have practiced the burning splints test for hydrogen in a previous investigation, compare the test for oxygen with the test for hydrogen, using a lit splint for both.

a) How are the procedures different?
The procedures are different by the splints that are used. In the oxygen test, a glowing splints is used. In the hydrogen test, on the other hand, a burning splints is used.

b) How do the observations differ?
For the hydrogen test, a pop was produced when the burning splint was placed with hydrogen. In the oxygen test, the glowing splint relit.

Conclusion:
I have observed that when the glowing splint is put in with oxygen, it relits. It's because in order to have fire, little amounts of oxygen must be present. For example, when one lights a candle, the candle holds flame because there are little concentrations of oxygen around it.

Photos:
Putting in the glowing splint in the test tube. As you can see, it relit.







**When the catalyst was put in the hydrogen peroxide.

***Glowing splint relighting.

***Picture when the dishwashing liquid was put in.