Colligative Properties
What are the characteristic colligative property changes when a non-volatile solute is added to solution
- Vapor pressure decreasing
- boiling point increasing
- freezing point decreasing
- osmotic pressure increasing
How do you know when you can use a small X approximation?
If the change is less than 5% of the reactant initial concentration
What is the difference between a Brønsted–Lowry Base and a Lewis base
Brønsted–Lowry base: Proton (H+) acceptor
Lewis Base: Electron donor
What is the difference between a galvanic and a voltaic cell?
There is no difference, they are the same thing!
Rank the types of forces between molecules in order of weakest to strongest
London dispersion forces -> dipole-dipole -> hydrogen bonding -> ion dipole
If an exothermic reaction is increased in temperature, which direction will the equilibrium shift
Equilibrium will shift towards the reactants (reverse)
What is it called when a species can act both as an acid or as a base
Amphoteric
True or false: An electrolytic cell makes electricity, it will therefore have a negative Ecell
false: while electrolytic cells do have a negative Ecell, they do not produce electricity (a galvanic cell does this). The negative Ecell represents the non-spontaneous nature of the cell, requiring energy be put into the cell for it to progress
When a solute dissolves in a solvent and yields multiple ions, it will effect the colligative properties of that substance. What is this effect called and how does it effect the colligative properties
i = Van't Hoff Factor
The Van't Hoff Factor multiples the product of any of the colligative properties by i or the amount of electrolytes in solution
True or false: If the Kc is greater than the Qc, the reaction is nonspontaneous and will not occur
False: a higher Kc than Qc would indicate the reaction has not yet reached equilibrium and will continue in the forward direction.
What is the relationship between ka and kb?
kw = ka kb
Ecell = Ecathode + Eanode
Is the Eanode in this equation an Ereduction or Eoxidation value?
Eoxidation
A beaker is filled with a non-volatile solvent dissolved in water. Identify what parts of the experimental set-up would correspond to what variables in Raoult's Law
Raoult's Law: Pa = Xa Pa*
Pa = partial pressure of water in solution
Xa = mole fraction of water in solution
Pa* = Vapor pressure of pure water
When considering equilibrium reactions, what types of species are not considered when writing the reaction constant equation
solid and liquid
During a titration of a weak acid and a strong base, at what point would you use the Hendersen Hasselbalch equation
When the amount of weak acid is more than the amount of strong base added
What are the 4 main rules for oxidation numbers?
- Oxidation number of atom in it's elemental substance is 0
- oxidation number of ions are equal to their charge
- Hydrogen is usually +1 and Oxygen is usually -2
- Sum of oxidation numbers in a molecule equals the molecule's charge
If 35.0 g of glucose (180.16g/mol) is dissolved in 400g of water, what is the change in boiling point? (kb = 0.512)
ΔTb=Kb⋅m
0.248∘C
Write the equilibrium constant equation for the following reaction
N2 (g) + O2 (g) -> 2NO (g)
k = [NO]2 / [N2] [O2]
Calculate remaining strong base in solution, finding the concentration of -OH
pOH = -log [OH]
pH = 14 - pOH
What molecule in a reaction of Cu (Ered = 0.34) and Fe (Ered = -0.04) would be at the cathode in an electrolytic cell?
Fe