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chemistry calculation questions help

First question:
How would you prepare 100 mL of a 1.5M Tris HCl (MW 157.59 g/L) stock?


Second question:

I have this formula but i do not know how i know the dilutio factor?
OD260X50ug/mlXdilution ratio= concentration of DNA.
1. pBluescript contains the ampicillin resistance gene and the lacZ gene. The MCS contains a number of restriction sites that could be used for cloning including EcoRI. You grow up a midipreparation of the plasmid DNA and resuspend the pellet in 0.200 ml of TE. You take 50 ul of the resuspended DNA and add it to 450 ul of TE and use this dilution to take an A260 reading to determine the DNA concentration. The A260 reading is 0.2. What is the concentration and yield of vector DNA that you purified? Show all of your calculations and units .
Concentration of vector DNA:__________________________________
Yield of vector DNA:____________________________________…
Cotinue just one question left related to this question

829 day(s) ago

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Answers (3)

First of all thanks alot for your help Mr. wish you luck all your life and again think to answer first question.

According to the first question i knew how to answer that before but i do not know how to find the dilution but i get it so

I post the formula which is OD260X50ug/mlXdilution ratio= concentration of DNA

So OD260 is 0.2 and the dilution is 10
so then
0.2X50ug/mlX10=100 i thik the unit will be ug/ml but i am not sure i will look for the unit.

thanks for your help , wish me luck with calculation the most difficult part for me.

Hope fully you will have success life and in coming day May be i will ask again ^_^

Posted 828 dy ago

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MFB13 		After reading your questions about the DNA, its not very clear based on how you wrote this. For example, when you read an optical density or spectral absorbance at 260 nm wavelength which I assume is OD260 which you wrote, you would need to know the relationship between different ODs and corresponding concentrations of DNA by setting up some sort of absorbance curve vs concentration or amount of something. Can you be more specific about this question because I just can't make too much sense of your protocol and the question you are asking. Please be more complete and a bit more clear about your question here. Thanks.

Posted 829 dy ago

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MFB13 		I am quite busy at this moment but I can answer your first question now.

Set up your relationship as follows to first find the number of grams you need to dissolve in 100 mL of deionized water or what ever solvent you are dissolving this in: that is

x g /[(0.100 L)(157.59 g/mol)] = 1.5 mol/L or 1.5 M

Note that the only term in the left handed numerator is x.

Now, solving for x, you get 23.6 g

So, you should dissolve 23.6 g of Tris HCl into 100 mL of your solvent.

Posted 829 dy ago

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