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Beer’S law and data analysis


  • Learn or review typical data analysis procedures–plotting data with excel, performing linear regression analysis, etc.
  • Explore the concepts and applications of spectrophotometry


  • Pre-lab (10%)
  • Lab Report Form–including plot (80%)
  • TA points + Pop Quiz (10%)

Before coming to lab…

  • Read the lab instructions
  • Print out the lab instructions and report form.
  • Complete the pre-lab, due at the beginning of the lab


When describing chemical compounds, scientists rely on their chemical and physical properties. In lab, we might observe that a metal reacts violently with water, that a reactant is liquid at room temperature, or that a powder is yellow. Chemical and physical properties can be used qualitatively to identify a material or to predict its behavior, or quantitatively to determine how much of that material is present in a solution. In this lab, we will develop a scheme to determine the concentration of copper sulfate in aqueous solution using spectrophotometry.

To start, we will consider light and its interaction with matter. Chemicals exhibit a diverse range of colors, especially when they contain transition metal ions. In order for a compound to have color, it must absorb visible light. Visible light consists of electromagnetic radiation with wavelengths ranging from approximately 400 nm to 700 nm, a small section of the electromagnetic radiation spectrum shown below.

Light is characterized by its frequency ( ν size 12{ν} {} ), the number of times the crest of the wave passes some point in space per second, or by its wavelength ( λ size 12{λ} {} ), the distance between two successive crests. These two quantities are related by the speed of light, a fundamental constant: λν = c = 3 × 10 8 m/s size 12{"λν"=c=3 times "10" rSup { size 8{8} } "m/s"} {} . Planck related the frequency of light to its energy (E) according to E = size 12{E="hν"} {} , where h is Planck's constant, h = 6 . 626 × 10 34 J/s size 12{h=6 "." "626" times "10" rSup { size 8{ - "34"} } "J/s"} {} .

A compound will absorb light when the radiation posesses the energy needed to move an electron from its lowest energy (ground) state to some excited state. The particular energies of radiation that a substance absorbs dictate the colors that it exhibits. Conversely the color of a compound can help us to determine its electronic configuration.

White light contains all wavelengths in this visible region. When a transparent sample (like most aqueous solutions) absorbs visible light, the color we perceive is the sum of the remaining colors that are transmitted by the object and strike our eyes.If an object absorbs all wavelengths of visible light, none reaches our eyes, and it appears black. If it absorbs no visible light, it will look white or colorless. If it absorbs all but orange, the material will appear orange. We also perceive an orange color when visible light of all colors except blue strikes our eyes. Orange and blue are complementary colors; the removal of blue from white light makes the light look orange, and vice versa. Thus, an object has a particular color for one of two reasons: It transmits light of only that color or it absorbs light of the complementary color.

Questions & Answers

Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Honors chemistry lab fall. OpenStax CNX. Nov 15, 2007 Download for free at http://cnx.org/content/col10456/1.16
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