equilibrium
Give the expression for Kc
Kc= [products]/[reactants]
Which of the following is/are not a strong acids/bases?
1. H2SO4
2. Mg(OH)2
3. HF
4. Ba(OH)2
2. Mg(OH)2
3. HF
What is the equation for pH?
what is the definition of a strong acid/base?
dissociates completely in solution
what element is the most abundant in the atmosphere?
Nitrogen (as N2 gas)
If K>Q which direction does the reaction proceed?
to products (right)
In a titration, if the starting pH in the erlenmeyer flask is low (<7) what kind of compound is in the burette?
Base
The pH of 0.100M solutions of each of the following were measured: NH3, NH4NO3 and HClO4. The values were, not necessarily in the same order: 1.0, 5.1, 11.1. Match the pHs correctly to the chemicals.
HClO4
NH4NO2
NH3
Ammonium bromide, NH4Br(aq), reacts with sodium dihydrogen phosphate, NaH2PO4(aq) via a Bronsted-Lowry H+-transfer reaction. Identify the spectator ions.
Na+ Br-
what macromolecle is the most abundant in the body?
proteins
what are the missing values for this ICE table? A(g) + 2B(g) ↔ 2C(g)
Initial (M) 0.842 0.666 0.112
Change (M)
Equilibrium (M) 0.334
what are the missing values for this ICE table? A(g) + 2B(g) ↔ 2C(g)
Initial (M) 0.842 0.666 0.112
Change (M). -0.166 -0.332. +0.332
Equilibrium (M) 0.676 0.334. 0.454
Which one statement is completely correct? Hint: Look carefully at the underlined words.
A) All strong acids have an acid ionization constant, Ka, of 1.
B) The conjugate of a weak acid has no acid-base properties.
C) An ionic compound in aqueous solution splits completely into its ions.
D) In a titration, the acid-base reaction reaches equilibrium only at the equivalence point.
E) At equilibrium, all the species in the reaction have exactly the same concentration.
C
Calculate the pOH of a solution with [H3O+] = 3.77 x 10-3M
11.58
Idenitfy the conjugate pairs of the following reaction
CH3NH3+ + CH3COONa --> CH3NH2 + CH3COOH
CH3NH3+ CH3NH2
CH3COO- CH3COOH
what are the 5 most common elements in the body?
C, H, O, N, Ca
If a reaction occuring in a sealed vessle is heated, which direction will the equilibrium shift?
2 SO2 (g) + O2 (g) ---> 2 SO3 (g)
Left
Which of the following statements is/are correct concerning the behavior when a small amount of strong acid is added to an HA/A- buffer solution?
1. The following reaction occurs: A-(aq) + H3O+(aq) ↔ HA(aq) + H2O
2. This results in the removal of all of the added acid.
3. The resulting solution is still a buffer solution.
1 and 3
Determine the pH (at equilibrium) of a 0.0207M solution (initial value) of the weak acid CH3COOH. Ka of CH3COOH = 1.75 x 10-5.
CH3COOH(aq) + H2O ↔ CH3COO-(aq) + H3O+(aq)
3.23
what is the definition of a BL acid and BL base?
Describe how electrons play a role in BL reactions
Bases are proton acceptors
Bases must have electrons to accept the incoming proton
acids must be able to hold on to electrons that once formed the H-X bond.
what is the last element made in stars before it starts to die. why?
iron
Calculate the equilibrium constant, Kc, of the Bronsted-Lowry H+ transfer reaction:
HCOOH(aq) + NO2-(aq) ↔ HCOO-(aq) + HNO2(aq)
Given: Ka of HCOOH is 1.8 x 10-4; Ka of HNO2 is 4.6 x 10-4.
0.39
what color do you observe when your phenolphthalein titration has gone bad? what color will you see when you have a successful titration?
hot pink!
very pale pink
Consider a weak base, B, with Kb = 2.75 x 10-4. A solution of 0.0642M B was prepared (initial value). Ionization of the base then occurred: B(aq) + H2O ↔ BH+(aq) + OH-(aq). Determine the pH of the solution when the reaction reached equilibrium.
11.62
Which one of the following is not a conjugate acid–base pair?
A. NH3 and NH4+
B. HS– and H2S
C. H3O+ and OH–
D. NH3 and NH–
E. H2PO4 – and HPO4-
H3O+ and OH–
How long has Dr. Golde been teaching at Pitt?
since 1977 (almost 50 years!)