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Can medium containing starch be autoclaved? - (Nov/21/2012 )

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Hi,

I'm decreasing the quantity because I want to use a small serium bottle for my stock solution.

Hmmm, I see your point. I can't use m1v1=m1v2 to solve for how much of the stock solution I need to use since I want to keep the concentration the same right? Maybe there is a more efficient way to do this? Now, I think I'm just confusing myself.

Maybe I should be preparing a greater concentration for my stock solution?

-SunsetSatine-

SunsetSatine on Thu Dec 6 23:52:14 2012 said:


Hi,

I'm decreasing the quantity because I want to use a small serium bottle for my stock solution.

Hmmm, I see your point. I can't use m1v1=m1v2 to solve for how much of the stock solution I need to use since I want to keep the concentration the same right? Maybe there is a more efficient way to do this? Now, I think I'm just confusing myself.

Maybe I should be preparing a greater concentration for my stock solution?


you can only dilute (stock) solutions. So if you allready have (stock) solution of 0,6gram per liter then you cant "dilute" this anymore without changing the "dilution".

If C1 is allready C2 then there is nothing to change/dilute...

-pito-

How does this sound?

For my NaHCO3, I prepare a 20% stock solution (10g in 50 mL DI Water)
M1V1=M2V2
(20%)(x)=(50mL)(0.4%)
X=1 mL

Reasoning, I have a 20% stock solution. I want to calculate how much of the 20% stock solution I have to add to my 50 mL of media, so that the final concentration of the NaHCO3 in the media is 0.4%.

Therefore, I add 1 mL of my 20% stock solution to 49 mL of media so that the final concentration of the NaHCO3 in the media is 0.4%.

-SunsetSatine-

SunsetSatine on Wed Dec 12 15:36:15 2012 said:


How does this sound?

For my NaHCO3, I prepare a 20% stock solution (10g in 50 mL DI Water)
M1V1=M2V2
(20%)(x)=(50mL)(0.4%)
X=1 mL

Reasoning, I have a 20% stock solution. I want to calculate how much of the 20% stock solution I have to add to my 50 mL of media, so that the final concentration of the NaHCO3 in the media is 0.4%.

Therefore, I add 1 mL of my 20% stock solution to 49 mL of media so that the final concentration of the NaHCO3 in the media is 0.4%.


1ml of a 20% stock solution means that of that 1ml only 20% is your "substance X", meaning 0,2ml
so 0,2ml in 50 ml total is indeed 0,4%
(0,2ml in 50 means, 0,4 in 100ml, so yeah...)

-pito-

That makes so much more sense. I will prepare my carbohydrate the same way now. I never thought to look at it that way before.

Thank you so much! That really helps!

-SunsetSatine-

SunsetSatine on Wed Dec 12 18:06:26 2012 said:


That makes so much more sense. I will prepare my carbohydrate the same way now. I never thought to look at it that way before.

Thank you so much! That really helps!


Its the same as what you did... I just "checked" whether you were right...

Its important to understand the logic behind it and not just use formulas you learned by heart.

-pito-

That makes sense. If I understand the logic behind it, then I can apply it to other situations in the future.

-SunsetSatine-

I'm having trouble getting my sodium bicarbonate to dissolved. I measured out 10g into 50 mL of DI water and it is just a cloudy solution. Since I can't heat the solution up, is there another way to dissolve it?

-SunsetSatine-

SunsetSatine on Wed Dec 12 20:58:18 2012 said:


I'm having trouble getting my sodium bicarbonate to dissolved. I measured out 10g into 50 mL of DI water and it is just a cloudy solution. Since I can't heat the solution up, is there another way to dissolve it?

9 g in 100 mL seems the maximum amount at room temperature.

-hobglobin-

SunsetSatine on Wed Dec 12 20:58:18 2012 said:


I'm having trouble getting my sodium bicarbonate to dissolved. I measured out 10g into 50 mL of DI water and it is just a cloudy solution. Since I can't heat the solution up, is there another way to dissolve it?


You should have checked the solubility.
From wiki: Solubility in water 9 g/100 mL

So bad luck...

Heating could help a bit, but in this case... that wont do much (and since you cant even do it...)
Make a new batch or dilute it more.

-pito-
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