Chemical reactions of copper lab answers

The cycle of Copper Reactions

The cycle of Copper Reactions

PROCEDURE

The cycle of a copper sequence of reactions for copper granules from its initial stage to the final recovered mass to make a cycle of copper reactions. Nonetheless, no copper is added or removed between the initial and final stages, as each reaction makes it to completion. According to the procedure given, there were no changes made as each step was followed to the recovery of copper.

In this copper cycle reactions, there are various observations from the chemical reaction from the initial to the final stage. Firstly, you need to have the copper material, in this case, the copper granules (Cu) where you mix with nitric acid (HNO3) will react to have copper Nitrate a solute substance Cu(NO3)2 (aq). The second procedure is having the copper nitrate mixing it with sodium hydroxide NaOH (aq) this react to form copper hydrate Cu(OH)2 (s) substance. Copper hydrate substance, therefore, is decomposed to have copper and oxygen as the third procedure. Sulfuric acid (H2SO4) is then added with copper and oxygen to have copper sulfate CuSO4 (aq). The final procedure was copper sulfate mixed with zinc a reaction occurred and zinc loses electrons to copper and ultimately has the copper mass recovered which is measured.

RESULTS

Table 1: Data Table on Mass Values

Measured Mass

Units (g)

Erlenmeyer flask

75.98

Copper granules

0.48

Erlenmeyer flask and dry copper

76.42

Mass of recovered copper

0.44

Percent of recovered copper

0.44

÷ × 100% = 91.6%

0.48

Table 2: Observations from reactions in the copper cycle

Reaction

Observations

Cu + HNO3

The copper bubbles after about 20 seconds change its color in blue and its darkens

Cu(NO3)2 + NaOH

It substance becomes thicker and darker as its color turns black

Cu(OH)2 +heat

Turns black

CuO + H2SO4

This turns to light blue

CuSO4 + Zn

The water becomes lighter in weight and copper pieces becomes reddish

Sample calculations:

0.44

÷ X 100% = 91.6666%

0.48

0.48 grams is the initial copper granules mass, as this underwent the entire process of the cycle until the final mass recovered being 0.44 grams. To achieve the above variables you calculate the final mass over the initial mass production of one hundred percent to get the 91.6% mass recovered.

Analysis of results

Copper having its initial mass underwent the copper cycle reaction with other metals and solvents. The mass of a substance will, either way, change its mass since it has free air as this will affect a bit low, there is also unreacted materials and this through the decanting process some of the sediments are left in very minute grams this, therefore, affected the final product of copper recovered.

Mass values

Measured mass

Units grams(g)

Erlenmeyer flask (step 2)

75.98

Copper granules (step 3)

0.48

Erlenmeyer flask and Dry copper (step 19)

76.42

Mass of recovered copper

0.44

Percentage recovered

91.6%

DISCUSSION

1. Identify the types of reactions observed and describe them in the same order as they are done in the experiment for the cycle of copper.

To begin with is reaction this is an oxidation-reduction (redox) reaction. This involves the transfer of electrons, in this case from copper to nitrogen having a chemical reaction of Nitric acid, copper granules and oxygen as the chemical materials used. The chemical formula is:

8 HNO3 (aq) + 3 Cu (s) + O2 (g) → 3 Cu (NO3)2 (aq) + 4 H2O (l) + 2 NO2 (g)

The solution ultimately found at the end of this reaction is copper nitrate and water and nitrogen gas escape to the atmosphere.

Secondly, is a double-replacement precipitation reaction, this, therefore, involves the nitrate and hydroxide ions switch partners as the copper hydroxide precipitates forms to be solid their chemical reaction is:

Cu (NO3)2 (aq) + 2 NaOH (aq) → Cu (OH) 2 (s) + 2 NaNO3 (aq)

Reaction three is a decomposition. The copper hydroxide ion breaks separately, leaving one oxygen combined with the copper. This happens to a copper hydroxide that was broken down to have water and copper with oxygen.

Cu (OH) 2 (s) → CuO (s) + H2O (l)

Reaction four is an acid-base reaction with a single replacement. The sulfate ion switches from the hydrogen to the copper, while the protons (hydrogen ions) combine with the oxide ion forming water their chemical reaction is:

CuO (s) + H2SO4 (aq) → CuSO4 (aq) + H2O (l)

The final reaction is a redox reaction in which zinc loses electrons to copper. Zinc being the chemical material and copper sulfur where zinc powder forms clumps in the solution to form zinc sulfate and copper material finally recovered. The chemical reaction is:

CuSO4 (aq) + Zn (s) → ZnSO4 (aq) + Cu (s)

1. What would be the effect of using a single, solid chunk of copper metal instead of the copper granules? What would be the effect of using powdered copper metal? Describe the factor or factors taken into consideration to answer this question. For solid chunk copper to be used, this would, therefore, make the reaction rate so slow and the time consuming thus granules are of preference. Powder copper oxidizes faster in the air on room temperature and thus prompting to change in color and for copper granules, it does not get affected

1. In step 4, you were warned not to let the solution bubble due to bumping or boiling. If the solution did splash out of the flask due to bubbling, would this affect your final product? Explain. If the solution gets spilled out of the graduated cylinder, this will ultimately affect the final solution since there are specified measurements of 10 mL of 5.0 M nitric acid (HNO3) using a 10mL graduated cylinder and that cannot be compromised. Unreacted materials also occur as this alters the final mass of copper recovered through heat loss and decanting process.

1. New pennies in the U.S are made approximate 95% from zinc metal and to make it look like copper in color it is therefore covered by copper foil on the outer side. In the US it was designed best in minting the pennies. To make a comparison in their characteristics and composition, pure solid copper weighs 3.11 grams while copper-plated zinc pennies weigh 2.5grams. Pennies, when dropped to listen to their sound, have a flat sound while copper has high-pitched melodious ring sound (Susan, 2019).

REFLECTION

This process in a view is informative on how different chemical reactions in this case copper being the main material reacts. It allows one to freely observe firsthand experience in different stages of the copper cycle and that also builds confidence to handle different chemical reaction procedures. A challenge being some of the chemicals may not react or buys more time to get the desired results in this case copper materials recovered reduced from the initial mass. Moving forward some of the chemicals may expire or their chemical concentration reduced thus affecting their reactivity. This, therefore, persons responsible should regularly check the details and concentrations of the chemical.