plz help me to write a complete lab report on the topic chemical reaction of cop
ID: 529469 • Letter: P
Question
plz help me to write a complete lab report on the topic chemical reaction of copper and the percent yeald
Explanation / Answer
CHEMICAL REACTIONS OF COPPER AND PERCENT YIELD KEY
1. OBJECTIVE
To gain familiarity with basic laboratory procedures, some chemistry of a typical transition element, and the concept of percent yield.
2. APPARATUS AND CHEMICALS
0.5 g piece of no. 16 or no. 18 copper wire
evaporating dish
250 mL beaker (2)
weighing paper
concentrated HNO3 (4 – 6 mL)
6.0 M H2SO4 (15 mL)
graduated cylinder
granular zinc
3.0 M NaOH (30 mL)
methanol
carborundum boiling chips
acetone
stirring rod
towel
iron ring and ring stand
balance
wire gauze
aluminum foil cut in 1-inch squares
Bunsen burner
concentrated HCl (drops)
3. DISCUSSION
Most chemical synthesis involves separation and purification of the desired product from unwanted side products. Some methods of separation, such as filtration, sedimentation, decantation, extraction, and sublimation were discussed earlier. This experiment is designed as a quantitative evaluation of your individual laboratory skills in carrying out some of these operations. At the same time you will become more acquainted with two fundamental types of chemical reactions - redox reactions and metathesis (double-displacement) reactions. By means of these reactions, you will finally recover the copper sample with maximum efficiency.
4. CHEMICAL REACTIONS
Cu(s) + 4 HNO3(aq) -----> Cu(NO3)2(aq) + 2 NO2(g) + 2 H2O(l) Redox [1]
Cu(NO3)2(aq) + 2 NaOH(aq) ------> Cu(OH)2(s) + 2 NaNO3(aq) Metathesis [2]
Cu(OH)2(s) -----> CuO(s) + H2O(g) Dehydration [3]
CuO(s) + H2SO4(aq) ------> CuSO4(aq) + H2O(l) Metathesis [4]
CuSO4(aq) + Zn(s) -----> ZnSO4(aq) + Cu(s) Redox [5]
objective in this experiment is to recover all of the copper you begin with in analytically pure form. This is the test of your laboratory skills.
The percent yield of the copper can be expressed as the ratio of the recovered weight to initial weight, multiplied by 100:
% yield = (recovered weight of Cu/initial weight of Cu) x 100
5. PROCEDURE
Weight approximately 0.500 g of copper turnings place it in a 250 mL beaker.
Add 4-5 mL of concentrated HNO3 to the beaker, IN THE HOOD.
After the reaction is complete, add 100 mL distilled H2O.
Add 30 mL of 3.0 M NaOH to the solution in your beaker.
Add two or three boiling chips and carefully heat the solution -- while stirring with a glass stirring rod -- just to the boiling point. Remove the boiling chips.
Allow the black CuO to settle; then decant the supernantant liquid. Add about 200 mL of very hot distilled water and allow the CuO to settle. Decant once more.
Add 15 mL of 6.0 M H2SO4.
In the hood, add 2.0 g of 30-mesh zinc metal all at once and stir until the supernatant liquid is colorless. When gas evolution has become very slow, heat the solution gently (but do not boil) and allow it to cool.
When gas evolution has ceased, decant the solution and transfer the precipitate to a preweighed porcelain evaporating dish (3). Wash the precipitated copper with about 5 mL of distilled water, allow to settle, decant the solution, and repeat the process.
Wash the precipitate with about 5 mL of methanol (KEEP THE METHANOL AWAY FROM FLAMES _ IT IS FLAMMABLE!) Allow the precipitate to settle, and decant the methanol. (METHANOL IS ALSO EXTREMELY TOXIC: AVOID BREATHING THE VAPORS AS MUCH AS POSSIBLE.)
Finally, wash the precipitate with about 5 mL of acetone (KEEP THE ACETONE AWAY FROM FLAMES - IT IS EXTREMELY FLAMMABLE!), allow the precipitate to settle, and decant the acetone from the precipitate. Prepare a steam bath as illustrated and dry the product on your steam bath for at least 5 minutes.
Wipe the bottom of the evaporating dish with a towel, remove the boiling chips and weigh the evaporating dish plus copper.
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