You place your sample in the spectrophotometer and find that A = 0.244. What is the % transmittance of this sample?
You place your sample in the spectrophotometer and find that A = 0.244. What is the...
In a spectrophotometer, both absorbance and transmittance indicate ------------- passing through a sample. A high absorbance corresponds to a ----------------transmittance.
Answers are in your own words. 1/ The Spectrophotometer --> Compare and contrast absorbance and transmittance. --> What is the purpose of the "blank"? 2/ Bacterial Growth and Optical Density: --> What is the relationship between turbidity and optical density? How might this change after 24 additional hours of incubation?
After purification of your favorite plasmid you use a spectrophotometer to find the concentration of your DNA and observe the graph below. Resketch by hand this graph on your answer page with exact axis labels and scales. Redraw the red line. Draw, in your estimation, the absorption spectrum of what is expected of a good DNA prep. OD o X Load your sample and press the measure button. Blank Re-Blank Sample ID: Pedestal ort pectra ple volume Type: DNA 50.00...
A, What does the UV-Vis spectrophotometer measure? What is Beer’s Law (you might have to look it up) and how does it relate to data collected from a spectrophotometer? B, What is a sample blank? What it is it used for in this experiment? C, What does the addition of NH3(aq) do to the copper(II) solution? If you don’t know because you haven’t yet done the experiment, make an educated guess. (Think about what the NH3 does chemically and what...
A student measures the absorbance of a sample of red dye #3 using a spectrophotometer. If the absorbance is measured as 0.468, what is the concentration of red dye #3 in the sample? Enter your answer in units of micromolar to three significant figures. n the lab spectrophotometer, d = 1.00 cm. For Red dye #3, ε = 7.96 x 104 M-1 cm-1.
The true absorbance of a sample is 1.500, but 0.50% stray light reaches the detector. Find the apparent transmittance and apparent absorbance of the sample. How much stray light can be tolerated if the absorbance error is not to exceed 0.001 at a true absorbance of 2? A research-quality spectrophotometer has a stray light level of greaterthan0.000 05% at 340 nm. What will be the maximum absorbance error for a sample with a true absorbance of 2? Of 3?
Qualitatively, how could you use a spectrophotometer to easily determine whether a green drink sample contains green dye molecules or a combination of both blue and yellow dye molecules? Be as specific as possible in your explanation.
When measuring your starch samples in a spectrophotometer, what sort of results would you expect to see if there were: a. different concentrations of starch in two tubes? b. How could you tell if there was the same concentrations of starch in two tubes? c. How could you tell if there was no starch in a tube?
0.422 gram sample of an unknown acid (HX) required 26.75 mL of 0.244 M NaOH for neutralization to a phenolphthalein end point. What is the molar mass of the acid?
4. A colorimeter (or spectrophotometer) actually measures percent transmittance (%T), as described in the appendix, and the LabQuest automatically converts that to absorbance. The relationship is logarithmic: Abs = 2 -log(%T) Imagine you have four solutions, and use the LabQuest to measure the absorbance of each one. You then convert to %T as below: Solution Absorbance % Transmittance W 0.250 56.23% 0.750 17.78% 2.250 0.562% Z 2.750 0.178% х Y Consider the sensitivity of the instrument. Do you think all...