A solution of methanol and water has a mole fraction of water of 0.312 and a total vapor pressure of 211 torr at 39.9 ∘C. The vapor pressures of pure methan ol and pure water at this temperature are 256 torr and 55.3 torr, respectively. ls the solution ideal? If not, what can you say about the relative strengths of the solute-solvent interactions compared to the solute-solute and solvent-solvent interactions?

Weaker

Explanation:

The strategy here is to use Raoult´s law to calculate the theoretical vapor pressure for the concentrations given and compare it with the experimental value of 211 torr.

Raoult´s law tell us that for a binary solution

P total = partial pressure A + partial pressure B = Xa PºA + Xb PºB

where Xa and Xb are the mol fractions, and  PºA and PºB are the vapor pressures of pure A and pure B, respectively

For the solution in question we have

Ptotal = 0.312 x 55.3 torr + ( 1- 0.312 ) x 256 torr     ( XA + XB = 1 )

Ptotal = 193 torr

Since experimentally, the total vapor pressure is 211 and our theoretical value is smaller ( 193 torr ), we can conclude the interactions  solute-solvent are weaker compared to the solute-solute and solvent-solvent interactions.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

because of all the things that happen around the us, many people get into arguments which sadly could get physical, but we should actually make a change for that.