# Recent content by Wek

1. ### Born Theory - Finding the value of Z (solvation of ions)

1. Homework Statement What's the energy for transfer from ε=1 to water with r=2.5Å ε=1 to water with r=5Å. 2. Homework Equations ΔG = (1/2)*(Z^2/r)*[(1/e1)-(1/e2)] 3. The Attempt at a Solution ΔG = (1/2)*(Z^2/2.5)*[(1/80)-(1/1)] However, I am stuck on the Z variable...
2. ### Calculate osmolality of a 0.1% and a 0.9% NaCl.?

Hm. If I use that formula I would need to use 0.001g of NaCl per 1kg of water to get a 0.1% solution. (0.001g/1kg)*(100) = 0.1% So to make 1 liter of 0.1% NaCl I need 0.001g of NaCl?
3. ### Calculate osmolality of a 0.1% and a 0.9% NaCl.?

The 1.8 dissociation constant was given. How much would the the NaCl grams of a 0.1% solution be then? The way I calculated the NaCl grams was by reasoning that if 1% = 1g/100ml then in 1000ml there would be 10g (10g/1000ml = 1%). So for a 1 liter of 0.1% NaCl solution there would be...
4. ### Calculate osmolality of a 0.1% and a 0.9% NaCl.?

I tried to calculate the osmolality (mOsm/kg) of a 0.1% and a 0.9% NaCl solution but I am not sure I'm doing this right. First I calculated the NaCl grams in a liter of solution, so for 0.1% I have 0.01g of NaCl. Then I divided by the 58.44 (MW) to get moles. Then I divided the moles by 1...
5. ### Help Solving Percent Molarity Problem

Use M1V1=M2V2. Don't need to go back to moles, percentages are fine.
6. ### Help calculating a diffusion rate using Fick's equation.

1. Homework Statement Assuming: Organism weight = 25 g Organism lenght = 30 cm [Na+ (ECF)] = 200 mM [Na+ (water)] = 500 mM ΔX(gill) = 6 μm ΔX(skin) = 25 μm A(gill) = 5.0 cm^2/gm A(skin) = 10 cm^2/gm Dk(gill) = 2 X 10^4 cm^2/s Dk(skin) = 1 X 10^4 cm^2/s Calculate the Na+...
7. ### How to choose plasmids for certain types of cell?

How do you know which plasmids are suitable (disregard the efficiency for now) for say, mammalian cells? For example, this http://www.addgene.org/12091/" [Broken] is it suitable for HeLa cells? Basically, I'm confused as to what "Growth strain" and "Vector type" mean. Does Growth strain mean...
8. ### RHR for Magnetic fields, why is it design in such a way?

I don't feel like this is a homework question, more like a curiosity question. If I'm wrong then feel free to move it to the homework section and my apologies. I know how the RHR works for magnetic forces and I can apply it with no problem, however I'm not a physics major so maybe I'm missing...
9. ### Raoult's law - Vapor pressure

This is what I did: -To find mole fraction of toluene I divided the vapor pressure of toluene solution by toluene's vapor pressure: 27.92/28.44 = 0.9817 -To get the moles of toluene: density x toluene volume then divided by toluene FW: 431g/92.0g = 4.68mol -Using the moles fraction equation...
10. ### Raoult's law - Vapor pressure

The density of toluene is 0.862g/ml at 25C and it's vapor pressure s 28.44 mmHg. At 25C, the vapor pressure of toluene above a solution of C10H8 in 500ml toluene is 27.92 mmHg. How many grams of C10H8 are present in the solution? I first used Raoult's equation to find X. Then I used the...
11. ### Would exonic primers affect gDNA amplification?

Will a primer designed for an exonic sequence anneal and sucessfully amplify a gDNA strand? I'm having trouble amplifying gDNA using that primer. cDNA with that primer amplifies perfectly. I have no problem amplifying gDNA using another primer that anneals to intronic sequences.
12. ### What kind of errors would be produced by excess taq in PCR?

What kind of errors would be produced by "excess" taq in PCR? Not sure if this belong in the Homework section. Put it here since it's not homework. What kind of errors will I get by adding 6.75µL taq pol to +50µL of cDNA? The master mix will be added to the cDNA resulting in an excess of taq...
13. ### Term Paper: Is the brain immunologically privileged?

Re: Term Paper: "Is the brain immunologically privileged?" Yes, the paper is basically about the BBB. That's actually a great topic. I was also thinknig about talking how Alzhimer's and some other diseases are involved wit the breakdown of the BBB.
14. ### Term Paper: Is the brain immunologically privileged?

Term Paper: "Is the brain immunologically privileged?" I have to write a term paper for my neuroscience class and the theme is "Is the brain immunologically privileged?". According to my professor I have a pretty nice introduction that explains the anatomical aspects of the brain that makes it...
15. ### HH Equation to calculate [HCO3-]

Yes, I used the HH equation to find the [HCO3] and it came out to be 13. I' not given any concentration for CO2 or H2CO3. In this case, how would you be able to find the concentration of CO2 or even H2CO3, if its possible at all? The value I used for [CO2] was something I found on Cornell's...