CHEM 2204

Chemical Laboratory Techniques

Browsing Posts published in April, 2016

As part of your lab writeup for Lab 5, you will need to hand in three properly labeled graphs:

Graph 1: Absorbance versus Wavelength – Indicate λmax and its value on the graph [Graph the fine scan only]
Graph 2: %Transmittance versus Wavelength – Indicate λmax and its value on the graph [Graph the fine scan only]
Graph 3: Absorbance versus Concentration – Run Linest on the data – Indicate the unknown sample on the graph by dropping a line from the absorbance of the sample to the x-axis. Indicate the concentration of the dilute sample and the original sample.

Read the detailed tips on how to plot these graphs.

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For Graph 1 and 2, after the data points are on the graph, right mouse click over one of the points and choose Change Series Chart Type … from the context menu. In the Change Chart Type popup, under (X,Y Scatter), choose Scatter with Smooth Lines and Markers.

This will draw a smooth curve through the data points.

Now add minor gridlines to the y-axis by right mouse click on the y-axis.

Choose Add Minor Gridlines. This will draw the minor gridlines for the y-axis.

Now add minor gridlines to the x-axis by right mouse click on the x-axis by right mouse click on the x-axis.

Choose Add Minor Gridlines. This will draw the minor gridlines for the x-axis.

With the minor axes drawn, this will allow you to interpolate the λmax value from the graph accurately.
Be sure to indicate λmax and its value on Graph 1 and 2.

For Graph 3, when you add the Linest function to the graph, be sure to enter false for Const. This will force the line to go through (0,0).

Be sure to indicate the unknown and its value on Graph 3.

Practical Assessment 2 will include assessing the following techniques:

  • Technique #1 – Use of a Burette
  • Technique #3 – Use of a Volumetric Flask
  • Technique #7 – Preparation of a Standard Solution
  • Technique #8 – Titration

In order to be well prepared for your first practical assessment, you will need to spend some time reviewing the techniques ( Techniques 1, 3, 7, 8 ) we covered.

Go to the laboratory page, and review:

  • Read the Preparation and marking scheme document
  • Read the Demonstrations of Nine Practical Lab Techniques
  • Download the schedules: Friday AM | Friday PM

Practical Assessment 2 will include assessing the following techniques:

  • Technique #1 – Use of a Burette
  • Technique #3 – Use of a Volumetric Flask
  • Technique #7 – Preparation of a Standard Solution
  • Technique #8 – Titration

In order to be well prepared for your first practical assessment, you will need to spend some time reviewing the techniques ( Techniques 1, 3, 7, 8 ) we covered.

Go to the laboratory page, and review:

  • Read the Preparation and marking scheme document
  • Read the Demonstrations of Nine Practical Lab Techniques
  • Download the schedules: Friday AM | Friday PM