AC 16 Colorimetric Analysis for Lab Notebook

7/21/2019 AC 16 Colorimetric Analysis for Lab Notebook

http://slidepdf.com/reader/full/ac-16-colorimetric-analysis-for-lab-notebook 1/7





Student Inquiry Worksheet

It is worth mentioning that the equation provides a more accurate estimate of the unknown concentration, since the

graph-based estimate can be subjective.

6. Colorimetric Analysis

*

Driving Question

How can you determine the concentration of a colorful solution?

Materials and Eui!ment

For each student or group

♦ Data collection system ♦ Graduated cylinder !0-m"

♦ Colorimeter ♦ #i$et %it& $um$ or bulb 10-m"

♦ Cu'ette ♦ Glass stirrin rod

♦ ensor e*tension cable ♦ 0.40 + co$$er(,,) sulate (Cu4) 30 m"

♦ /eaers () 100-m" ♦ Distilled %ater 30 m"

♦ Test tubes (2) lare ♦ +arin $en

♦ Test tube rac ♦ as& bottle %it& distilled %ater

"a#ety

Follow all standard laboratory procedures.

Procedure

After you complete a step (or answer a question), place a check mark in the box ( ) next to that step.

Set !p

1. Connect the colorimeter to the data collection system using the extension cable.

2. Start a new experiment on the data collection system. Click on Sparkvue and then Build.

* This is an AP Chemistry course recommended experiment.




3. Con!igure the data collection system to manually collect absorbance o! orange "#$ nm% light and the

concentration in a table. To do this scroll down and click on &'ser entered numeral data(. )or measurementtype in &concentration( and !or unit name type in &molarity(.

4. ext click on both absorbance orange and concentration. Then click on the table button and

ok. +n the bottom by the clock, click on it and change to manual.

5. Calibrate the colorimeter with the blank solution "use distilled water !or the blank%. To do this rinse a

cuvette with a small amount o! &blank( solution - empty. ext !ill the cuvette. ipe clean and dry and place itinto the colorimeter. Press the green button and the light will go on. /eave in until the light goes o!!.

6. ater absorbs a small amount o! light.

7. /abel !our clean, dry test tubes &( through &0( and place them into a test tube rack.

8. Pipet 1.$, 0.$, #.$, and 2.$ m/ o! the $.0$ 3 copper"44% sul!ate solution into test tubes through 0,

respectively.

9. 5eliver 2.$, #.$, 0.$, and 1.$ m/ o! distilled water into test tubes through 0 so that each test tube has

$.$ m/ o! solution.10. Thoroughly mix each solution with a stirring rod.

Note: Clean and dry t&e stirrin rod beore stirrin a dierent solution.

Table : olumes and concentrations or t&e calibration solutions

Trial # 0.40 M CuSO4 (mL) HO (mL) Concentration (M)

Colorimeter

"i&t -ti&t co'er

Calibration button

5*tension cable (o$tional)

1 3 4

) t o c 0

6 n 0 n o % n




1 2.0 8.0 0.08

2 4.0 6.0 0.16

3 6.0 4.0 0.24

4 8.0 2.0 0.32

5 10.0 0 0.40

ollect Data

""# Start a new, manually sampled data set. Click on and then the arrow button. Click on theconcentration trials and enter the concentrations above !or the !irst 6 test tubes.

12. 3easure the absorbance o! the !ive known solutions !ollowing the steps below.

a. 7inse the cuvette twice with a small portion o! the !irst solution and then !ill the cuvette two8thirds !ull.

ipe the cuvette clean and dry and place it into the colorimeter.

b. &Turn on( the colorimeter by clicking the &on( button. A!ter the reading stabili9es, record a data

point by clicking on the green button again.

c. 5ispose o! the solution appropriately and rinse the cell thoroughly with water.

d. :ach time you place a new cuvette in, wait !or it to stabili9e and again click to record. hen you haverecorded all o! your data, stop the data set by clicking on;

Note: T&e data or test tube 2 is not yet recorded because it &as an unno%n molarity and it %ill not be $art o t&e

standardi7ation cur'e.

13. Save your experiment. To do this click on and then save as<.

=

Data Analysis

1. Create a data table to record the concentration an absorbance o! the 6 solutions. Also include a place torecord the unknown "to be done later in the lab%

2. To graph your data start a new page by clicking on . Select the absorbance orange and

concentration again, but now click on the graph button and ok.

3. Ad>ust the scale o! the graph to show all data, i! needed.




4. )ind the slope o! the best8!it line. To do this click on and then . Select &/inear )it( an

ok.

5. Print the graph. Click on the camera and then . Click on ?ournal and then print >ournal.

6. Attach your graph o! Concentration versus Absorbance.

=

$esting t%e &n'no(n

1. 3onitor +range "#$ nm% Absorbance data in a digits display. Start a new page, click on orange

absorbance and then

2. 3easure the absorbance o! the sixth "unknown% solution. 7ecord the +range "#$ nm% Absorbance in the

data table and clean up according to your teacher@s instructions.

3. 'se the euation !or the line to calculate the concentration o! the unknown. Show all o! your work.

4. 'se the calibration curve to estimate the concentration o! the unknown.




4

Documents

AC 16 Colorimetric Analysis for Lab Notebook