Lab 1: Solutions and Spectrophotometry Flashcards
Familiarize yourself with the following concepts and skills: Conceptual: 1. Using a spectrophotometer to determine a solution concentration 2. Interpret information contained in an absorption spectra and Standard Curves. 3. Generate and interpolate from a line of best fit Skills: 1. Measure and pipet large volumes 2. Obtain/ graph spectrophotometric data. 3. Calculate final solution concentrations from a dilution using the appropriate formula
What does it mean to interpolate?
to determine a value from an existing value in a data sheet
Define the following terms:
1. Solute:
2. Solvent:
3. Concentration:
4. Molarity (Moles)
- is what is being dissolved in a solution
- What is doing the dissolving
- how much of a solute is dissolved in a solvent
- how many molecules are dissolved.
What is the concept of dilution:
refers to the process of reducing concentration of a solute by increasing the solvent. The relationship is as follows:
Dilution- More Solvent- decreased concentration.
What is the formula for measuring the final contration of a solution after dilution?
C1V1=C2V2
C1= Initial Molar concentration
V1= Initial volume
C2= Final Molar Concentration
V2= Final Volume added
What is the unit of measurement for concentration:
mM which is the # of millimoles of solute per L of solution
What is spectrophotometry:
a method used to measure how much light a substance absorbs at different wavelengths.
What are two purposes for why biologists use spectrophotometers?
- Determine the concentration of an absorbed material
- Determine the absorption spectrum of a colored solution.
How does the machine calculate the concentration of a solution?
When light passes thru a solution, some of the lights gets absorbed by the solute in the solution. The more concentrtaed the material, the more light it absorbs. By measuring how much light is absorbed, the concentration is then calculated.
Explain what an absorbance spectrum is?
each solution absorbs light at a specific wavelength, and therefore AS shows how mucg of that light is absorbed at different wavelengths. This creates a graph showing what colors were abosrbed or not, called an Absrbance Spectrum
What are wavelengths and what do they refer to?
refers to the various forms of light. When
