acid/bases
How do you find percent ionization?
You need molarity of the solution: [M]. Either given or calculated from given mass and volume.
You need calculate the concentration of hydroxide or hydronium ions at equilibrium: [x].
% ionization = [x]/[M] x 100
What substances are soluble? (Remember NAGSAG)
Nitrates, Acetates, Group 1s, Sulfates, Ammonium, Group 17s
The electrode that loses mass
Anode
What changes K?
Temperature only. Increasing temperature increases the average kinetic energy of molecules, so more molecules will overcome the activation energy, and the reaction will be faster.
What are the 3 problem types that give us information to find change in enthalpy (Delta H) ?
Given heat of formations, Hproducts - Hreactants
Given heat of formation of reactions, add them
Given bond enthalpies, BEreactants - BEproducts
How can you get Kb if you already know Ka?
Kw = Ka x Kb = 1 x 10-14
Kb = 1x10-14/Ka
What are the 6 strong acids?
HCl, HBr, HI, HClO4, H2SO4, HNO3,
Indicates a working battery
G < 0
Voltage > 0
units of K for a first order reaction
s^-1
What units are Gibbs free energy, entropy, and enthalpy typically given as?
Gibbs free energy (G): kJ/mol
Enthalpy (H): kJ/mol
Entropy (S): J/K.mol
Why is pH = pKa at half equivalence point?
half the acid is neutralized, so [HA] = [A⁻], making pH = pKa.
what are the strong bases?
group 1 hydroxides (like NaOH, KOH) and
heavy Group 2 hydroxides (like Ca(OH)₂, Sr(OH)₂, Ba(OH)₂)
What is the purpose of the salt bridge?
To maintain electrical neutrality by allowing ions to flow
If you multiply a reaction by a constant to change the coefficient numbers, what do you do to K, the equilibrium constant?
raise the K to the power of the constant
how can you predict if entropy (ΔS) increases in a reaction?
If products are more disordered than reactants like solid to gas, or more gas molecules formed then ΔS is positive.
Why does a weaker acid have a stronger conjugate base?
Because acid and base strength are inversely related meaning A weak acid doesn’t donate protons easily, which means its conjugate base has a higher tendency to accept protons thus making it stronger.
what types of compounds are always strong electrolytes?
strong acids, strong bases, and soluble ionic salts.
in which direction do electrons flow?
From the anode to the cathode through the external wire.
Two experiments show doubling [A] doubles the rate, but doubling [B] has no effect. What does this tell you about the rate law?
The reaction is first order in A and zero order in B thus only A affects the rate, so only A appears in the rate law.
Why can a reaction with a negative ΔG still not proceed?
Because thermodynamics tells you if it can happen not how fast. A high activation energy can make it kinetically slow.
why is there a sharp vertical jump in pH at the equivalence point of a typical acid base titration?
At the equivalence point all the acid and base have neutralized each other. There’s no buffer present thus even a slight addition of titrantg causes a large change in pH
What experimental technique involves isolating and weighing a solid product to determine the amount of a specific ion or compound in a sample?
Gravimetric analysis
In an electrolytic cell a non-spontaneous redox reaction occurs. What external condition is required for the cell to function and how is it different from a galvanic cell?
power source is required to force the reaction to occur unlike a galvanic cell which generates its own electricity from a spontaneous reaction
The overall rate law of a reaction can sometimes include a catalyst.
True
How does the combination of ΔH and ΔS signs determine whether a reaction is spontaneous, and when?
ΔH (–), ΔS (+) → Spontaneous at all temperatures
ΔH (+), ΔS (–) → Never spontaneous
ΔH (–), ΔS (–) → Spontaneous at low temperatures
ΔH (+), ΔS (+) → Spontaneous at high temperatures