lab

Intro

In Lab #5 five we will be exploring the cycle of copper through many chemical reactions. What we are going to do is take a piece of copper metal put it through a series of reactions that change it¡¦s state of matter and chemical formula, but in the end, we will return it to it¡¦s normal solid state. The idea of this lab is to try to recover as close to 100% of the copper we started with. Theoretically, this is possible, but for inexperienced college students, retrieving 100% of the copper metal is near impossible. There are five reactions that the copper will go through.

1. 3Cu(s) + 8HNO3(aq) + O2 „³ 3Cu(NO3)2(aq) + 4H2O(aq) + 2NO2(aq)

2. 3Cu(NO3)2(aq) + 2NaOH(aq) „³ Cu(OH)2(s) + 2NaNO3(aq)

3. Cu(OH)2(s) „³ CuO(s) + H2O(aq)

4. CuO(s) + H2SO4(aq) „³ CuSO4(aq) +H2O(aq)

5. CuSO4(aq) + Zn(s) „³ ZnSO4 + Cu(s)

At the end of reaction number five we should have close to 100% of the copper we started out with.

Meth

Obtain as close to .5g of copper wire, and record the mass to the closest mg. Make sure the wire is bent so it will lay as flat as possible in the bottom of a 250mL beaker. Then go to ¡§the hood¡¨ and add 4mL of 16M HNO3. Swirl the HNO3 around in the beaker with the copper until it has completely dissolved and you are left with a green/blue liquid. Then add 30mL of 3M NaOH and heat the solution on a ring stand with a Bunsen burner. The blue/green jelly will turn in to sort of a black dirt at the bottom of the beaker, make sure to stop boiling when the jelly turns black. Decant all excess liquid in the beaker. Do not remove any black precipitate. Add approximately 200mL of hot deionized water to the black precipitate. Decant all excess liquid again. Add 15mL of 6M H2SO4 and then under ¡§the hood¡¨ add 2g of Zinc metal to the solution. Once the Hydrogen has stopped bubbling add 10mL of HCl. Decant all excess liquid and transfer Copper metal to a glass dish and wash with deionized water. Rewash Copper metal with 5mL of Methanol. Decant and dry Copper metal on a hot plate, weigh and record results to nearest mg.

Resu

Original Mass of Cu=.486g

Mass of Cycled Cu=.480g

1. In the first reaction the was brown smoke and the copper turned into a light blue/green liquid.

2. In the second reaction the solution turned into a clear blue liquid.