Mixtures

Question 1

What types of solutions exist

Answer 1

1. Solution formed by componenty miscible in all proportions(water+ethanol). Composition is defined through molar fractions of different component
   Xi=ni/n ; n=Σni ; Σxi=1
   2.Dilute solutions=one solvent(i=0) with solutes(i=1,2,3…) at low concentration

Question 2

What variable is used for solvent in molar fractions

Answer 2

Xi≈1

Question 3

Formulas for molarity

Answer 3

[i]=ni/V(solution)≅ni/V(solvent)=ni/(mass×ro)=ro×mi
mi=molality

Question 4

Formulas for molality

Answer 4

mi=ni/Msolvent=ni/(M(0)×n(0)=Xi/M(0)
M(0)=molar mass of solvent in kg

Question 5

Formula for molar fraction

Answer 5

Xi=ni/(n0+n1+n2..)≃ni/n0

Question 6

What is Raoult law

Answer 6

pi=Xi×pi*

Question 7

What is formula for Gibbs free energy for binary solutions

Answer 7

G(l)=n(1)μ(1,l)+n(2)μ(2,l)

Question 8

If chemical potential for liquid and gas phase is equal l, what is the formula.

Answer 8

μ(i,l)=μ(i,g)=μ(i,g,)⊝+RTln(pi/p⊝)
If th3 go by Raoul law that ln(pi/p⊝) becomes ln((Xi×pi*)/p⊝)

Question 9

What is formula for chemical potential of pure liquid

Answer 9

μ(i,l)=μ(i,g)⊝+RTln(pi/p⊝)

Question 10

Taking into account formula for chemical potential of pure liquid, what is formula for chemical potential of liquid

Answer 10

μ(i,l)=μ(i,l)*+RTln(Xi)

Question 11

What is Henry’s law

Answer 11

For x->0 ; pi=Xi×Ki
Ki=Henry’s constant

Question 12

What expression is used when there exists deviations from Raoult’s law

Answer 12

Activity coeffixient yi
μ(i,l)=μ(i,l)*(T,p)+RTln(yi×xi)

Question 13

What is generalozation of Raoult’s law taking into account activity coefficient

Answer 13

pi=pi*×Xi×yi

Question 14

What is formula for chemical potential of the solvent

Answer 14

μ(0,l)=μ(0,l)*+RTln(X0)

Question 15

What is standard molality

Answer 15

1mol/kg

Question 16

What is standard state of the solute

Answer 16

Solution at standard p and with standard molality, assuming that it follows Henry’s law in these conditions

Question 17

What is chemical potential of solute

Answer 17

μ(i,sol)=μ(i,sol)⊝(T)+RTln(mi/m⊝)
And if it deviated from Henry’s law
Then yi is added to ln(yi mi/m⊝)

Question 18

How is molar fraction in gas phase calculated

Answer 18

Y=pi/ptot=ni/ntot OR Xi×pi*/ptot