lab report 7

CHEM16682 APPLIED CHEMISTRY 1LABORATORY REPORT

Professor: Alexandra chernish

Name: Bhumika Patel Class Day/Time: Thursday (8am-10am)

Title of Lab: Chemical reaction of copper

Date Lab Performed: Nov, 06, 2014 Due: Nov, 13, 2014

Date and Time Report Submitted (by Professor): _____________________

Partner’s Name: Mina Niazi

Late Penalty: ________________________

BHUMIKA PATEL991351597 1

NOTE: Please note that lab reports without a copy of the signed original results will not be marked.


CHEM16682, Experiment 7

Laboratory 7: Reactions of Copper and PercentYield

Purpose /2

The purpose of this experiment is to observe the chemistry of copper cycle in aqueous solution done through 5 chemical reactionand to determine the percentage yield of Copper.

Procedure /2

Procedure of this experiment is same as given in Applied Chemistry 1 Experiment 7- Chemical Reaction of Copper template given on the SLATE. There are not any changes in the procedure.1

Observations

1. Create your own data table for quantitative data. The tablemust include all the measurements you recorded in the laboratory. It must have a table number and title.

/4

Table 1. Quantitative data for copper

Mass (g)Mass of 250ml beaker 117.84Mass of Cu (Initial Cu mass)

0.49

Mass of the empty flat 47.48



bottom evaporating dishMass of evaporating dish and Cu product

48.04

2. In table format record your qualitative observations for each of the five reactions. All must be written in completesentences. The table(s) must have a table number and title.

/5

Table 2. Qualitative observation for reaction 1

Reaction 1 Cu(s) + HNO3(aq) →

Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)

Physical state Solid Aqueous Aqueous Gas Liquid

Colour Brown Colourles

s

Light

blue

Brown Colourles

sChemical Name Copper Nitric

acid

Copper(II

)

nitrate

Nitroge

n Gas

Dihydroge

n

monoxideAdditional reaction observations

Heat is generated during this chemical reaction.




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

Physical State

Aqueous Aqueous Solid Gas

Colour Light blue Colourless Blue BlueChemical Name

Copper(II)nitrate Sodium hydroxide

Copper hydroxide

Sodium nitrate

Additional Reaction Observations

After addition of NaOH blue precipitates are formed.


Reaction 3



Cu(OH)2(s) + Heat → CuO(S)

+ H2O(g)

Physical State

Solid Solid Gas

Colour Blue Black ColourlessChemical Name

Copper hydroxide

Copper oxide Dihydrogen monoxide


After heating black precipitates are formed andthen settled down


Reaction 4 CuO(S) + H2SO4(aq) → CuSO4(aq) + H2O(l)

Physical State

Solid Aqueous Aqueous Liquid

Colour Black Colourless Light blue ColourlessChemical Name

Copper oxide

Sulphuric acid

Copper sulphate

Dihydrogenmonoxide

Additional Reaction

All solid has been dissolved in the liquid and liquid became light blue.



Observations


Reaction 5 CuSO4(aq) + Zn(s) → ZnSO4(aq) + Cu(s)

Physical State

Aqueous Solid Aqueous Solid

Colour Light blue Gray Colourless BrownChemical Name

Copper sulphate

Zinc Zinc sulphate

Copper


Heat is generated during this chemical reaction.

3. Write balanced chemical equations for each of the five reactions. Identify and name the reactants and the product(s) for each reaction. State whether he chemical is a solid, liquid or gas.

/5

Cu(s) + 4HNO3(aq) → Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)Copper Nitric acid Copper(II)nitrate Nitrogen gas Dihydrogen monoxide (1)



Cu(NO3)2(aq) + 2NaOH(aq) → Cu(OH)2(s) + 2NaNO3(aq) Copper(II)nitrate Sodium hydroxide Copper hydroxide Sodium nitrate (2)

Cu(OH)2(s) + Heat → CuO(S) + H2O(l)Copper hydroxide Copper oxide Dihydrogen monoxide (3)

CuO(S) + H2SO4(aq) → CuSO4(aq) + H2O(l)Copper oxide Sulfuric acid Copper sulfate Dihydrogen monoxide

(4)

CuSO4(aq) + Zn(s) → ZnSO4(aq) +Cu(s)Copper sulfate Zinc Zinc sulfate Copper (5)

4. For each of the five reactions, identify the reaction type(s). Your choices are: decomposition reaction, oxidation-reduction reaction, acid-base reaction, combustionreaction, single displacement reaction, double displacement reaction and synthesis reaction.

/3

Reaction 1

Cu(s) + 4HNO3(aq) → Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)Copper Nitric acid Copper(II)nitrate Nitrogen gas Dihydrogen monoxide (1)

Type of reaction: Decomposition reaction

Reaction 2



Cu(NO3)2(aq) + 2NaOH(aq) → Cu(OH)2(s) + 2NaNO3(aq) Copper(II)nitrate Sodium hydroxide Copper hydroxide Sodium nitrate (2)

Type of reaction: Double displacement reaction

Reaction 3

Cu(OH)2(s) + Heat → CuO(S) + H2O(l)Copper hydroxide Copper oxide Dihydrogen monoxide (3)

Type of reaction: Decomposition reaction

Reaction 4

CuO(S) + H2SO4(aq) → CuSO4(aq) + H2O(l)Copper oxide Sulfuric acid Copper sulfate Dihydrogen monoxide

(4)

Type of reaction: Double displacement reaction.

Reaction 5

CuSO4(aq) + Zn(s) → ZnSO4(aq) +Cu(s)Copper sulfate Zinc Zinc sulfate Copper (5)

Type of reaction: Single displacement reaction

Calculations



1) Calculate the % yield of Cu at the end of the five reaction steps. (This could also be referred to as the % recovery ofCu.) Show ALL calculations.

/3

Original mass of Copper (g) = 0.49 g

Final Mass of Copper (g) = Mass of evaporating dish and Cu product (g) -

Mass of empty flat bottom evaporating dish (g)

= 48.04 g – 47.48 g

= 0.56 g

Percentage yield (%) = FinalmassofCuobtainedOriginalmassofCu x 100%

= 0.56g0.49gx 100% = 114.28%

≈114%

2) For Reaction 1 between Cu and HNO3, calculate the theoretical yield of Cu(NO3)2 in grams. Confirm that the HNO3 used for this reaction was present in excess.

/5

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



MM Cu = 63.546 g Cu/ mol Cu

MM HNO3 = (1.008 + 14.007 + 3(15.999))

= 63.012 g HNO3/ mol HNO3

MM Cu(NO3)2 = ( 63.546 + 2(14.007) + 6(15.999))

= 187.554 g Cu(NO3)2/ mol Cu(NO3)2

Mole of Cu available = 0.49 g Cu × 1molCu63.456gCu =

0.0077 mol Cu

Theoretical yield of Cu(NO3)2

=0.0077 mol Cu ×1molCu(NO3)21molCu × 187.554gCu (NO3)2

1molCu(NO3)2

= 1.4 g Cu(NO3)2

3) For Reaction 2, calculate how many moles of NaOH you added.

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



MM Cu(NO3)2 = ( 63.546 + 2(14.007) + 6(15.999))

= 187.554 g Cu(NO3)2/ mol Cu(NO3)2

Mole of NaOH = 1.4 g Cu(NO3)2×1molCu(NO3)2

187.554gCu (NO3)2×2molNaOH

1molCu(NO3)2

= 0.0149 mol NaOH = 0.015 mol NaOH

Questions1. What compound was being removed in the procedural step where 200 mL of hot R.O. water was added to the solid CuO precipitate? Do you think that all of this compound was removed by this washing? How would this error affect your percent yield of Cu? How could this error be minimized?

/6 When 200 ml of hot R.O. water was added to the solid CuO

precipitate in the beaker, NaNO3 was being removed because of its aqueous nature. Entire compound was not removed by the washing due to incomplete dissolution. Some of the particles were still present with the CuO precipitates and can’t be removed by washing, so the amount of the product will be increased. It can affect the percent yield of Cu. This error is known as Method error.



Method error can be minimized by making appropriate changes in the procedure such as washing a precipitate more than once to remove contaminants, and also by increase the dissolution process.

2. Describe in detail: a) two sources of error that may have increased your percent yield of Cu and b) two sources of error that may have decreased your percent yield of Cu

/6(a). Two source of error in this experiment that may haveincreased the percentage yield of Cu are as under.

1. By washing method, we cannot remove the entire amount of theNaNo3 particles from the CuO particles because of improperdissolution. So it increased the mass of the final productwhich affected the percent yield of Cu.

2. In the final step, Zn does not completely reacted with theCuSO4.Some particles of the zinc still remains with theCopper. It increased the mass of the final Cu. Because ofthis we got more mass of than real mass. It changed thepercent yield of Cu.

(b). Two source of error in this experiment that may havedecreased the percentage yield of Cu are as under.

1. During the decantation of the liquid some particle went tothe beaker with the liquid so there was loss of somematerial which decreased the percentage yield of Cu.

2. Some particle were remain in the beaker during transfer tothe another beaker or glassware so it reduced the weight ofthe material that affected the percent recovery of copper.



Conclusion(s) /3

From this experiment we can conclude that the final mass of cu obtained after the completion of copper cycle in aqueous solutionwas found to be 0.56g which is more than the initial Cu mass. Thepercentage yield was found to be 114%.

Reference(s) /21. Applied chemistry 1 Experiment 7- Chemical Reaction of Copper

template given on the SLATE. Pg. no. 1-5

Teacher Evaluation (Students leave this part blank)

Overall organization of lab report: formatting of chemical and mathematical equations; clarity of answers; spelling and grammar;attention to details; completed cover sheet; use of headers and footers.

Laboratory performance: punctuality; time management; team work;attention to safety; use of personal protection equipment; using appropriate lab techniques; preparation of lab data book in advance of the lab; cleanup of lab work area.

/5

Total laboratory grade: /53



Professor’s suggestions for improvement:


lab report 7

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