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Here you will find material for Experiment 4 - Copper Chemistry. This includes detailed guides for the pre-lab, data sheet, post-lab, and quiz questions. Remember, the lab may change or be modified from semester to semester!

The objective of this lab is to demonstrate the Principle of Conservation of Mass by performing reactions with copper and analyzing the amount of copper after the sequence of reactions are performed. The product you obtain from the last reaction will be left with the TA to dry. The TA will contact you or your lab group regarding your copper yield. This data will be used to complete the assignment.

 

Experiment 4 is broken up into five main reactions and 2 side reactions that may be asked on quizzes:

  • Reaction 1 (redox): Cu(s) + HNO3(aq) → Cu(NO3)2(aq) + H2O(l) + NO2(g)
    • HNO3 is a strong acid
    • NO2 is toxic
  • Reaction 2 (metathesis): Cu(NO3)2(aq) + Na2CO3(s) + H2O → CuCO3•Cu(OH)2(s) + NaNO3(aq) + CO2(g)
    • Reaction 2a (acid-base): HNO3(aq) + Na2CO3(s) → NaNO3(aq) + CO2(g) + H2O(l)
  • Reaction 3 (decomposition): CuCO3•Cu(OH)2(s) + heat → CuO(s) + H2O(l) + CO2(g)
  • Reaction 4 (metathesis): CuO(s) + H2SO4(aq) → CuSO4(aq) + H2O(l)
  • Reaction 5 (single displacement or redox): CuSO4(aq) + Mg(s) → MgSO4(aq) + Cu(s)
    • Reaction 5a (single displacement or redox): H2SO4(aq) + Mg(s) → MgSO4(aq) + H2(g)
      • H2 flammable gas, ensure bunsen burners are off
 

Reaction 1: Cu + HNO3 → Cu(NO3)2 + H2O + NO2

This will be the first reaction where you will record the initial mass of the cooper wool used. You will also record your observations of the copper solution. It is important to note that this is a redox reaction as it may be asked on a quiz.

 

Reaction 2: Cu(NO3)2 + Na2CO3 + H2O → CuCO3•Cu(OH)2 + NaNO3 + CO2

The second reaction is a metathesis reaction (may be asked quizzes). Product is taken from the prevous reaction to perform this reaction. You are asked to describe the appearance.

 

Reaction 3 : CuCO3•Cu(OH)2 + heat → CuO + H2O + CO2

This is the third reaction and is a decomposition reaction (my be asked on quizzes). Product is taken from previous reaction.

 

Reaction 4 (metathesis): CuO + H2SO4 → CuSO4 + H2O

This is the fourth reaction and is a metathesis reaction (may be asked on quizzes). Products from the previous reactin are taken and you are asked to describe the appearance.

 

Reaction 5 (single displacement or redox): CuSO4 + Mg → MgSO4 + Cu

This will be the last reaction and is a redox or single displacement reaction (may be asked on quizzes). Product is taken from the previous reaction. You will be asked to describe the appearance, record the yeield, and compare it with the initial.

 
 

what you need

Below or a list of items you will need for lab. These items can be bought at the campus bookstore and from UH American Chemical Society (ACS). However, you may find these cheaper on sites like Amazon (links below).

 
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CALCULATOR (LINK)

A scientific calculator is needed for calculations on quizzes. Some labs have calculations that need to be turned in before leaving.

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LAB GOGGLES (LINK)

Required eye protection. Must be worn at the start of the experiment and until leaving

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COMBINATION LOCK (LINK)

A combination lock is required to lock your equipment drawer for the semester.

 
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LAB COAT (LINK)

A lab coat is required and must be worn once lab begins.

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LAB MANUAL (LINK)

Specifically, General Chemistry Laboratories A Freshman Workbook. The lab manual will have all the experiment procedures you will be performing during the semester including their respective datasheet and postlab questions

 
 
 

what to expect

The information provided below are things you will need to know and understand to complete this experiment successfully. We have also included parts of the lab that may give you difficulties, potential bottlenecks and workarounds so you can finish the experiment efficiently. Remember, the information given by TA should have the highest importance and supersedes all information provided on this page.

 

bottlenecks

This experiment is performed through a sequential set of reactions. Thus, you cannot skip reactions and how quickly you are able to perform each reaction will determine the bottlenecks you encounter.

 
 

Things to Focus on

Calculating percent yield

This lab will require you to calculate the percent yield of the copper. Percent yield is calculated by dividing your actual yield (mass of copper yield after the last reaction and drying) with the expected or theoretical yield (mass copper you initially used) multiplied by 100.

Percent Yield = (Actual Yield ÷ Theoretical Yield) x 100

 

A percent yield that is less than 100 means that you made less than what you were supposed to get. This could be a number of reasons such as loss of substance during transfer.

A percent yield that is more than 100 means that you have more than what you were supposed to get. This could be a number of reasons such as impurities or that the sample was not completely dry.

 

Observations

Be elaborate with your descriptions. State the obvious such as color but you can also the include behavior. Do not just put one word description. Some TAs have been known to deduct points for descriptions not being elaborate enough. You will have to figure out how your specific TA grades.

 

safety

Pay attention to these following. They may show up on your quiz.

  • HNO3 strong acid
  • NO2 toxic, inhalation hazard
  • H2 flammable gas, ensure bunsen burners are off