[beethoven24680]

I am conducting an experiment where I need to dilute a powder to 0.75 mg/mL. I have a stock solution of powder (150g). I need to make approximately 10 mL (doesn't need to be exact) of the diluted solution. How much water will I need to add to the powder to make this concentration of 0.75 mg/mL. And, what will my dilution factor be? Thanks in advance for help.


Note: I've been trying to work on this for a while, with ideas ranging from M1V1=M2V2 to intuition. My work is pretty much jargon because different approaches are giving me different answers. I may just be over thinking this.

[Archer]

You are over thinking this, particularly if it doesn't need to be exact (although it would help if you told us which part did not need to be exact, the concentration or the volume)

If there are 0.75mg in 1ml, how many mg are there in 10ml, 100ml or 1000ml?

Still having trouble, if there is 30g per 1 bag of crisps, how many g in 10 bags?

I have a stock solution of powder (150g).

Do you mean you have 150g of powder or is there a volume missing here for your "stock solution"

[beethoven24680]

What I meant to say is that I need no less that 10 mL of the diluted solution. I probably won't be using it all during the experiment, but this amount should be more than enough.

So, to make 10 mL at a .75mg/mL concentration, I would need to add 7.5 mg of powder to 10 mL of water? If this is correct, what would the dilution factor be? Would it be 1:10?

[Vidya]

to get 0.75 mg/ml solution and you need 10 mL of the solution
0.75/1=x/10
x= 0.75*10 = 7.5mg in 10 ml
here you are making a solution of desired strength and you are not diluting any solution.So it is not clear which dilution you are talking about?

[Archer]

I would need to add 7.5 mg of powder to 10 mL of water?

 

Yes but 7.5 mg is difficult to measure precisely so you would be better off making the solution 10 times more concentrated (i.e.75 mg in 10 ml) and diluting this stock 1:10.

[beethoven24680]

Okay, so we conducted the experiment and found that our sample (in each cuvette containing 1 mL BioRad and 20 microliters of our sample) contained 0.436 mg protein/mL of sample. The sample was with 75mg of protein powder mixed with 10 mL of water. I want to convert our found value (0.436 mg protein/mL of sample) to grams of protein in 150 grams of powder so I can compare it with what is reported on the nutritional label.  Does that make sense? In essence, I want to find out how much protein I would have in my sample if I had a serving size of 150g of powder. The serving size on the nutritional label is 150 grams and in that 150 grams, there is supposed to be 50 grams of protein. How can I do this? I asked my professor and he gave a confusing answer.