Tuesday, May 18, 2010

How to make copper out of Copper Sulfate

Introduction:
In our lab we try and show the use of the percent yield formulas and how they can be useful in a lab situation. We use the formulas to figure out how much of the copper we will get out of the solution of Copper II Sulfate Pentahydrate and Aluminum flakes. Its very a effective way of figuring out how much is produced considering that the whole class is not going to have the same exact measurements meaning there are gonna be several different answers and equations threw out the whole class. This is a help yourself and a learn it yourself type of lab meaning you'll probably remember it a lot better then if your instructor were to stand in front of you and do it all for you.
The reaction taking place in this lab is a Single displacement reaction, due to the Copper sulfate being changed by the Aluminum flakes and the water turning the once blue flakes of Copper Sulfate into that copper color we see all the time on the ground facing heads up I hope. The percent yield is to show how much leeway you have in a lab to mess up or how much other people will mess up. The activities series is a very valuable tool in this lab, it aids to predicting the products of replacement reactions.

Purpose:

To determine the number of grams of copper that will be produced from an oxidation reduction reaction when you know the mass of Aluminum that reacted with a known amount of copper II sulfate pentahydrate and to compare this to the actual yield of copper. Also to determine the percent yield of Copper II Sulfate Pentahydrate by determining the theoretical percent yield.
Materials and Setup:
You will obtain a measured sample if aluminum foil and a measured amount of copper sulfate pentahydrate. You will then react the two in a n aqueous medium within a medium sized beaker: stirring frequently. You will filter, dry, and weigh the resulting product.

Procedure:
1. Obtain a medium sized( 250 to 400 ml) beaker.
2. add 75 to 100 ml of water to beaker: set-up apparatus to heat your mixture over a Bunsen burner to begin heating.
3. measure out about 15g of Copper (II) sulfate pentrahydrate (CuSo4* 5H2O) and record the mass in the data table. Then slowly add the crystals to the heating water.
4. with a glass stirring rod, stir the solution until the Copper II sulfate pentahydrate is dissolved.
5. while the copper sulfate crystals are dissolving one member of the group can go and get the foil. Carefully weigh out a piece of aluminum foil that weighs between .7 to 1.0 grams. Record the mass exactly into the data table (thousandths place).
6. Tear the foil into small pieces and carefully add it to the hot solution with continuous stirring until all the foil is placed into the beaker.
7. Stirring frequently allow the reaction to occur until you cant see anymore silvery foil pieces. This will take 15 to 20 minutes so be patient. Once you can't see anymore foil pieces no matter how small, heat and additional 3 to 4 minutes, then remove from the heat.
8. write your names around the outside edge of a filter paper(so you can claim it later), weigh and record the mass in the data table.
9. use the filter paper and your funnel to filter the residue in the beaker, catching the filtrate into the Erlenmeyer flask provided.
10. Rinse out your beaker with a small (amount just covering the bottom of the beaker) of water to be sure you obtained all of the product/ residue.
11. Remove the filter paper from the funnel and spread it out on a paper towel to dry overnight.
12. Clean and dry the glassware. Be sure the propane is turned off and Bunsen burner disconnected and put away. Straighten up the area.
13. Upon returning the next day. Weigh the filter paper and dry residue and record that mass in the data table. Throw filter paper and residue away.
14. Construct a data table with the following parts:
mass of copper II sulfate pentahydrate
Mass of aluminum foil
mass of coffee filter
Mass of dry Residue/product+filter paper.


Safety:
In this lab safety is a big issue considering you are working with a Bunsen burner and potentially hazardous chemicals. So you should wear the proper safety gear, such as: Goggles, aprons, gloves and make sure that your instructor is in the room just in case something crazy like and explosion happens. Make sure you know where all the First Aid kits are and make sure that you know how to use the eye washer and shower stations just in case you get some of the chemicals explode on to you or your eyes.Also be aware where your fire blanket is in the room since we are dealing with fire. Be sure that if there is any broken glass to put it into the the designated area in your class room. We'd rather no one lose and eye during this product.

During Procedure:
During this procedure we used various amounts of lab equipment to make sure that it was a safe fun lab! During you need to make sure that you are taking notes on some of the variables that are subject to change such as the amount of copper used or aluminum flakes this is very important (reason for putting it twice).

Making a Table:
You need to make a table during this to make sure that you have all the information that you need down (yet again). ITs very Important! also balanced equations would help you in making a table....But be sure to double check your equation so you dont look silly for getting it wrong. If you have any issues in solving the problem go to your instructor and see if he is willing to save your poor soul:]. I would have provided my table in for demonstration purposes but sadly it was drenched in water and became impossible to read and I don't want to do the lab allllllll over again. Sorry for the inconvenience. P.s. its very important to make sure that all partners just for this rare occasion copy or write the table as well, just that if your paper is completely submerged in water because babies think thats funny, don't make the team completely screwed.

Conclusion:
Your end product for this lab is a copper tented mass at the bottom of your funnel, measure how much it weighs and the use a percent yield equation to figure how far off you were from the theoretical yield. When you have completed this put that information into the table and then your all done! You have now successfully completed the lab and you can now go rub it in your teachers face cause you did it by your self right? Well you better have, considering that it was actually a fairly easy lab:) but its ok to ask for help. When you are all done you can look back and remember how easy it was to do theoretical and percent yield equations, how balanced equations are useful in this lab, how figuring out the reaction before hand in your balanced equation is a way to better discuss and help you realize how cool it was too see it happen. IN conclusion you learned sooooooo much hopefully.

Friday, March 19, 2010

TYPES OF REACTIONS!!!!! *boom*

Statement of the Problem:

Our goal is to be able to preform the different chemical changes, distinguish what kind of chemical change happened by our observations and be able to identify the products.

Materials:

In this lab we needed safety gear (goggles and apron), test tube rack, 1-3 test tubes, bunsun burner, sparker, clamp, reactants ( piece of zinc, about 1/2 mL CuSO4 solution, about 1/2 mL Ba(NO3)2 solution, about 1/2 mL HCl solution, magnesium ribbon, about 2 mL H2O2)

Procedure:

1. Obtain three small test tubes

2. in the first test tube,place a piece of zinc and about 1/2 ml of CuSo4 solution. Record observations.

3. In the second tube add about 1/2 ML Ba(NO3)2 solution to about 1/2 mL of CuSO4 solution. record observations.

4. In the third test tube place a piece of magnesium ribbon. add about 1/2 mL of HCl solution. Record Observations.

5. Light a Bunsen burner (burning propane gas, C3H8). record observations.

6. Rinse out the first test tube. Add about 2 mL H2O2 solution. lightly heat it. Record observations.

7. Add a pinch of MNO2 (catalyst) to the H2O2 solution. Lightly heat it. Record observation.

Results (Data):

Reactions Product Observations Reaction Types
Zn+CuSO4 ZnSO4+ Cu Brown precipitate, copper formation Single Displacement
Ba(NO3)2+
CuSO4
BaSO4+
Cu(no3)2
Milky white/blue liquid, white precipitate, cold, color change Double Displacement
Mg+HCl H2+ MgCl2 Clear bubbles, Heat, Hydrogen gas released (popping explosion) Single Displacement
C3H8+O Co2+ H2O Lit on fire when spark was added Combustion
H2O2 H2O+ O2 Making popping boiling, Oxygen gas released (splint got brighter) Decomposition








Zn+CuSO4






C3H8






H2O2







Mg+HCl




Conclusions:

* Include a sum

mary of the data - averages, highest, lowest..etc to help the reader

understand your results
* List one thing you learned and describe how it applies to a real-life situation.
*Discuss possible errors that could have occurred in the collection of the data

*answer discussion questions

Friday, February 26, 2010

Polarity and Molecular Shape Lab

Title:

Polarity and Molecular Shape LAB

Statement of the Problem:

1. Construct models of molecules

2. Determine molecular shapes

3. Predict polarity of molecules

Materials:

Molecular model Kit

Procedure:

In this lab we built a 3-dimensional model for every molecule , after constructing the models we drew a 3D representation, using different lines to represent the different directions of the bonds and types of bonds.



















Results:

This is a table of the molecular formula, shape of molecule, bond angle, whether or not it has polarity, and if it is a resonance structure.










Analysis Questions:

1) Explain how water's shape causes it to be polar.

The electrons are pulled toward the more electronegative atom in the molecule. In water's case it is oxygen that is the most electronegative and since the bonds with the two hydrogen atoms form an angular molecule it leaves the side with oxygen's full valence orbitals exposed so hydrogen's exposes positive nucleus and oxygen's exposed electrons makes it a very polar molecule.

2) Describe how water's properties would be different if the molecules were linear instead of bent.

If water was linear there would be no exposed sides (thus symmetrical) and the electrons wouldn't accumulate toward any one side.

3) Based on the results of this experiment. List the molecules from the expirement that would be water-soluble.

C3H8, Si2H6, HF, H2O2, IF3, SF6, SO32-



Friday, February 5, 2010

Lab Chromatography Lab Report


Statement of the Problem:

Which solvent of the four we are using (C6H14, CH3OH, C3H7OH, H2O) is best pulling pigments from ink?

Paper chromatography is an important separation technique that depends on differences in both absorption and solubility. Each component of the mixture will move a definite distance on the paper in proportion to the distance that the solvent moves. This ratio can be calculates for each component, to aid in identification. Retention factor values are dependent upon the paper, devoling solution, and sample size.

(retention factor) Rf = distance component moves / distance solution moves


Hypothesis:

Water will separate the different pigments from the ink.


Materials:

H2O, CH3OH, C3H7OH, C6H14

Mixtures to separate: Water-soluble overhead pens (black, red, green, black, red, yellow, blue)

Solid Phase: Chromatography paper strips (10) - 1cm x 8cm

Procedure:

First we gathered the materials we needed for Part 1 of this lab ( four 1cm x 8cm paper strips, a black marker, a small sample of each of the the solvents to fill up half a 24 well plate

Results (Data):

* The separation of the dyes within the marker where affected by the type of chemicals they were soaked in.
* Different markers had different dyes which were shown as the chemicals separated the dyes.


Conclusions:

Our hypothesis was highly supported.
It was supported because during the lap water best separated the dyes within the markers color .
Water separated the dyes most effectively, CH3OH separated the dyes less effectively then the water but more effectively the the C6H14 which had a better separation then C3H7OH which separated the least amount of dyes (but gave headaches).
Water is a highly effective solvent and this is why it is the international solvent.
The amounts of the solvents if they weren't the same, the ink being dipped to deep into the solvent , amount of ink used, and the amount of paper dipped into the solvents