CHEM Lab R- Copper Cycle PDF

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Chemistry Lab Report on Copper Cycle...

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COPPER CYCLE ABSTRACT Copper is a chemical element which is known to be recyclable. A specific amount of copper wire was subjected to a series of different reactions. Nitric acid was poured in a beaker with copper. When fumes were no longer being produced, distilled water then sodium hydroxide was added. The mixture was then boiled and filtered. The filtrate, upon adding sulfuric acid was dissolved and a zinc metal was added. The mixture was then heated, washed with methanol and acetone and decanted after each washing. The yield was completely dried via water bath before weighing. The percentage yield was then computed. The experiment was successful for the yield was 94% of the original amount.

INTRODUCTION Copper(Cu), a reddish-brown metal, with excellent thermal, electrical conductivity and corrosion resistance properties 1. Its application ranges from wires and plumbing to modern electronics 1. Not only is Copper is the most widely used metal, it is also the most reused metal 2. Due to its infinite recyclable life and can be used repeatedly in any form. Nearly as much of the copper is recovered from recycled scraps each year, as its extracted from newly mined copper ores 2. Chemical reactions allow for the production, extraction and recycling of elements. The three major classes of chemical reactions are precipitation reactions, acid-base reactions, and oxidation-reduction or redox reactions 3. Precipitation reactions results in the formation of insoluble particles or precipitate that separates from the solution 3. Acid-base reactions occur when an acid reacts with a base to form a salt and water 3. The acid is an H+donor, while the base becomes an OH-donor 3. Redox reaction is a transfer of atoms between the two species, either gaining or losing electrons 3. The most common types of Oxidation – reduction reaction are combustion, decomposition, double replacement and single replacement reactions 3. During combustion reaction substance react with oxygen to produce heat and light 3. During decomposition reactions, a compound breaks down into two or more components 3. In double replacement reactions, the cations and anion of two reactants are exchanges 3. While in single replacement reactions, either the cation or the anion of two compounds are switched 3. Theoretically, the amount of element should be the same from beginning of the reaction and amount received at the end. This is due to John Daltons law of conservation of mass which states that “matter can be neither created nor destroyed” 3. Meaning that the mass of the product in a reaction must be equal to that of the reactants 3. Therefore, the mass of element at the beginning of experiment should yield the same mass at the end 3. The aim of this experiment was to put copper through a sequence of chemical reaction, known as ‘copper-cycle’ and return it to its original solid form. Observe the type of reaction occurring and provide evidence that the reaction occurred. This will test the law of conservation of mass and laboratory efficiency in the production of greatest yield. It was hypothesized that the mass of the retrieved copper will be the same as the starting amount before the experiment. This is due to the Law of conservation of mass, which states that there will be no change in the mass for the element thought out an experiment 3.

METHOD MATERIALS Approx. 1.5g Copper (CU)

Zinc metal 5g (Zn)

Wash bottle

Sulphuric Acid 2M (H2SO4)

Stirring rod

100 mL Measuring cylinder

Sodium Hydroxide 6M (NaOH) Concentrated Nitric Acid (HNO3)

250mL Beaker Small Beaker

Red litmus paper Watch glass

Acetone non-halogenated

Waste bottle

Hotplate

Safety Precaution Concentrates acid and bases are used in this experiment. Severe burns can be cause if not removed promptly when contact with skin. Nitric acid reaction must be done is fume hood. Keep Acetone away from flames as its highly flammable solvent. Disposable gloves, goggles, lab coats and enclosed shoes must be worn during this experiment.

PROCEDURE Step 1: Reaction of Copper with Nitric Acid Firstly, empty 250mL beaker was weighed and mass was recorded. Then Copper was added into the beaker and re-weighed, mass of Cu was 1.186g used. In the fume hood, 15 mL of nitric acid was added to the beaker containing the Cu and it was covered with a watch glass. The beaker was left in the fume hood until all the copper has reacted and reaction was completed, the beaker may be swirled gently to decrease the waiting time. Step 2: Preparation of Copper(ll) Hydroxide To the solution prepared above, 6 M sodium hydroxide (NaOH) was carefully added with constant stirring. Until the solution turned basic, indicated by red litmus paper turning blue when placed into the solution. Step 3: Preparation of Copper(ll) Oxide 100 mL of Distilled water was added to the beaker, which was then placed on the hotplate in low heat and contents was stirred constantly with stirring rod. Failure to stir constantly can cause the solution to superheat and explode. Heating of the solution was stopped when it started to boil and particles from stirring rod was washed into the beaker. Solids has formed at the bottom as the mixture was left to cool to room temperature. The clear liquid was poured off into the waste container without losing any solids. Then 100mL of distilled water was placed into the beaker which was left for the solid to settle in the bottom. The clear solution was again poured into waster container without losing the solids. The solid was kept for the next stage. Step 4: Converting Copper(ll) Oxide to Copper(ll) Sulfate Carefully 50 mL of Sulphuric Acid (H2SO4) was added to the beaker, stirring rod was used to mix the solution until the precipitate was completely dissolved. Step 5: Recovering the Metallic Copper 1.392g of Zinc(Zn) metal was weighed and added to the solution in the beaker. The beaker was covered with a watch glass and occasionally swirled. Finally, the solution was poured into the vacuum filtration apparatus and the copper obtained was washed with 3-5mL of acetone, which was left to dry as the air was drawn through the filter.

RESULTS Reaction A: Copper with Nitric acid Copper + nitric acid → Copper(ll) nitrate +nitrogen dioxide+ water Cu (s) + HNO3 (aq) →Cu(NO3)2 (aq) + NO2 (aq) +H2O (l)

Before Reaction -Copper is brown and at room temperature

Observation (Refer to Appendix Fig 1 and 2) During Reaction After Reaction -Colour and state change from -The solution is clear and blue in solid brown- green- blue liquid colour -Production of heat and orange -Temperature decreased to smoke room temperature

Reaction B: Preparation of Copper(ll) Hydroxide Copper(ll)nitrate+ Sodium hydroxide→ Copper(ll) hydroxide +Sodium nitrate Cu(NO3)2 (aq) + 2NaOH (aq) →Cu(OH)2 (s) + 2NaNO3 (aq)

Before Reaction -Solution colour was blue and at room temperature -NaOH was colourless

Observation (Refer to Appendix Fig 3) During Reaction After Reaction -The solution colour changed -Thick black solution is produced from blue to black and more -Litmus paper turned blue viscous indication solution is basic -Heat and smell being released -Small amount of light blue solution is left on the side of beaker

Reaction C: Preparation of Copper(ll) oxide Copper(ll) hydroxide Cu (OH)2 ∆ →

∆ Copper (ll) oxide +water →

CuO (s) + H2O (L)

Before Reaction -Slightly thick and black solution

Observation (Refer to Appendix Fig 4) During Reaction After Reaction -Colour changed from black to -Solution remain dark dark brown/black during heating brown/black -After 10 minutes black precipitate settled at the bottom.

Reaction D: Preparation of Copper(ll) sulfate

Copper(ll) oxide + Sulphuric acid → Copper (ll) sulfate +water CuO (s) + H2SO4 (aq) → CuSO4 (aq) + H2O (l)

Before Reaction

Observation (Refer to Appendix Fig 5) During Reaction After Reaction

-Black, sand like liquid

-Instantly the solution turned from black to clear blue liquid

-The solution is clear blue copper (ll) nitrate.

Reaction E: Regeneration of Metallic Copper Copper(ll)sulfate+ zinc → copper + zinc(ll) sulphate CuSO4 (aq) +Zn(s) → Cu(s) + ZnSO4 (aq) Zinc(ll) sulphate + sulphuric acid +hydrogen ZnSO4 (aq) +H2SO4 → ZnSO4 (aq) +H2 (g) Before Reaction -Clear blue solution -Litmus paper turns red indicating it acidic.

Observation (Refer to Appendix Fig 6,7 and 8) During Reaction After Reaction -Zinc colour changed from silver -Red coloured zinc left and to black (black substance black/ gold substance floated at covered it) the surface. -Bubbles were formed, and heat -Cloudy addition of acid turned released solution to clear. -Copper retrieved after vacuum filtration.

Table 1: Observation recorded throughout the lab for the different types of reaction copper went through.

DISCUSSION

CONCLUSION

REFERENCES

1. Copper Development Association. Copper: Properties and Applications. Copper Alliance Group.2015. Accessed from http://copperalliance.org.uk/education-and-careers/education-resources/copperproperties-and-applications 2. Copper Development Association. Copper - the World's Most Reusable Resource. Copper Alliance Group.2015. Accessed from http://copperalliance.org.uk/education-and-careers/educationresources/copper-properties-and-applications 3. Chang, R. General chemistry: the essential concepts. 5th edition. N.Y. McGraw-Hill Inc.2008

http://npalayman.weebly.com/uploads/5/3/9/2/53928255/four_rxn_cu_cycle.pdf https://www.scribd.com/document/248582033/The-Copper-Cycle-Lab https://www.scribd.com/doc/21268144/Chemical-Reactions-of-Copper-Lab https://www.scribd.com/document/116097464/Copper-Reactions https://www.scribd.com/doc/94219258/From-Copper-to-Copper-Lab https://www.scribd.com/document/172906717/Copper-Cycle-Lab https://www.scribd.com/doc/87615001/Lab-Formal-Chemistry-of-Copper http://s.hbeteam.net/General%20Chemistry.pdf

APPENDIX

Figure 1: When Nitric Acid was added to the Copper in the beaker. Reaction taken place in the fume hood.

Figure 2: When Nitric Acid and copper reaction was finished blue solution(copper(ll) nitrate) is in the beaker.

Figure 3: When Sodium hydroxide was added to the Copper(ll) nitrate (blue solution) in the beaker. Colour changed to black.

Figure 4: When Copper(ll) hydroxide was heated and left to cool. Solids settled at the bottom of the beaker and water is the clear liquid.

Figure 5: When Sulfuric acid was added to the Copper(ll) oxide in the beaker. Colour changed from black to blue.

Figure 6: When Zinc metal was added to the Copper(ll) sulfate in the beaker. Black substance formed and covered the zinc metal.

Figure 7: When the black substance slowly floated to the top.

Figure 8: After vacuum filtration of the solution the copper obtained is shown above....