Acid-Base Equilibria
What is the purpose of a titration?
to determine the concentration of an analyte by reacting it with a titrant
homogeneous mixtures of two or more substances
Define equilibrium.
When the rates of the forward and reverse reactions are equal, the concentrations of the reactant and product species remain constant over time.
What is solubility?
Solubility is the ability of a substance (the solute) to dissolve in another substance (the solvent) to form a solution.
What is the keq expression?
[products]/[reactants] TO THE STOICHIOMETRIC COEFFICIENT
Fill in the blank: Solutions form ______________.
spontaneously
What type of arrows and tables do you use with equlibrium?
double arrow with ICE table
What is the equilibrium constant?
Ksp; does not include solids
What is needed to have a buffer?
CA/B pair with a difference of only one proton.
What are the main colligative properties?
boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure
Explain Le Châtelier’s principle.
if an equilibrium system is stressed, the system will experience a shift in response to the stress that re-establishes equilibrium.
What factors affect solubility?
Polarity of solute/solvent
temperature
pressure
A titration is carried out for 25.00 mL of 0.100 M HCl with 0.100 M of a strong base NaOH. Calculate the pH when 25.00 mL of base is added.
(c) Titrant volume = 25.00 mL. This titrant addition involves a stoichiometric amount of base (the equivalence point), and so only products of the neutralization reaction are in solution (water and NaCl). Neither the cation nor the anion of this salt undergo acid-base ionization; the only process generating hydronium ions is the autoprotolysis of water. The solution is neutral, having a pH = 7.00.
What are the mole fraction and molality of a solution that contains 0.850 g of ammonia, NH3, dissolved in 125 g of water?
7.14 × 10−3; 0.399 m
The German chemist Fritz Haber was able to synthesize ammonia (NH3) by reacting 0.1248 M H2 and 0.0416 M N2 at about 500°C. At equilibrium, the mixture contained 0.00272 M NH3. What is K for the reaction N2 + 3 H2 ⇌ 2NH3 at this temperature?
K = 0.105
Your nemesis has prepared a perfectly saturated solution of CaF2. To sabotage their work, you add 10 M NaF to their solution. How many grams of CaF2 fall out of solution if they had prepared 500 mL.
0.00839 g