Lately, I've been looking and thinking about the fact that a professor told us in an advanced physiology lecture. When it came to mentioning osmotic pressure and the Van't Hoff relationship:
p = cRT
he said it was just an approximation, and if we ever got bored, we should try to prove it mathematically. I remember this relationship from when I took physical chemistry classes but I never looked into it further. Well, since I was bored, I started looking at the derivation of this relationship and possible clues to why it is just an approximation, and it kind of messed with my head.
Is it because in this part [1]:
p = -(RT/Vm) * ln(1-xs)
we can apply Taylors series for ln(1-xs) in the case of very dilute solutions? Is the result of Taylor's development a relationship that we can also sometimes see, when instead of concentration c we calculate the sum of the product of concentration and activity for each osmotically active substance in dilute solutions? Does this part of the relation tell us that it is a simple approximation? And how can I somehow mathematically prove it?
I have this question about what salt would be best to melt snow on a sidewalk, and the method my professor wants us to solve it with is by just kind of reasoning it out using a freezing point depression formula, ΞTf=i*Kf*m. The answer I picked (which is also correct) is MgCl2 because it has a Van't Hoff Factor of 3, and would increase the amount the freezing point is lowered by. What I'm unsure of is an alternative answer, which is PbS2. To my knowledge this also has a Van't Hoff Factor of 3, so wouldn't this yield the same results as MgCl2?
Sorry if my explanation is confusing at all, here's an image of the question at hand: https://imgur.com/a/6JIA3Uo
Hey so I understand that NaCl will break off into 2 ions but I don't see why i = 4 for Na3PO4, because I don't see why the oxygen is ignored. It's explained as 3 sodium ions and 1 phosphate ion but I would have counted the 4 oxygens as well -- is there a reason for this?
https://preview.redd.it/fvx4tal133871.png?width=933&format=png&auto=webp&s=aeb255b20a100c0981c40681c3f081182ce35590
I've been thinking about this for a while, could a healthy Arthur Morgan potentially 1 vs All the entire gang? Its such an unlikely outcome out of any situation, but I wanna hear your thoughts.
Van Hoff's equation relates enthalpy to the equilibrium constant in this way: ln k1/k2 = (H/R) (1/T2 - 1/T1).
Arrhenius equation relates activation energy to equilibrium constant in this way: ln k1/k2 = (-Ea/R) (1/T2 - 1/T1).
My question is, wouldn't this imply that Ea = -H, which is obviously nonsensical? Where is the flaw in my logic?
I have an excel file with multiple data observations, I want a tool where I can filter the data by solvent and by solute and then plot 2 particular columns against each other. I would also like linear regression line and a Y value predictor. Can anybody help? Here is where I have got to so far and it nicely plots the filtered data:
#Reading the file
df = pd.read_excel(r'C:\Users\pickl\Desktop\Local.xlsx', sheet_name='Solubility')
solv_and_sol= df[(df["Solute"]=="Lamivudine") & (df["Solvent"]=="Methanol")]
Y = solv_and_sol['lnx']
X = solv_and_sol['1overT']
#Plot
plt.scatter(X, Y, color='black')
plt.title('Vant Hoff')
plt.xlabel('1 over T')
plt.ylabel('ln x')
plt.show()
Little confused on the phrasing of this question and just wondering if I did it right:
- What would you expect the vanβt Hoff factor to be for an aqueous solution of each of the following: a) NaOH? B) CH3OH? C) K2CO3?
I said :
a) 2 for NaOH
b) 1 for CH3OH
c) 3 For K2CO3
https://twitter.com/MyLegacyKit/status/1467941231938396170
Sound like defamation to me.
Why is it that when the dilution approaches infinity, the Van't Hoff factor is the expected value. That doesn't make sense to me because what if that one ionic compound is still associated. Wouldn't it make sense that the more the ionic compounds, the greater the chances of there being dissociation? I don't get why it's one way or the other. Can someone please explain?
