General Chemistry II Exam #4 CLP Questions
What is the [H+] in a solution containing both 0.50 M HF and 0.10 NaF?
3.4 x 10^-5 M
Determine whether entropy increases or decreases for each situation below. a. condensation of steam to liquid b. formation of a precipitate in solution c. dissolving a salt into solvent d. solid water subliming to steam
a. decreases b. decreases c. increases d. increases
Calculate the value of Kn for the neutralization reaction of H2SO3 with NaOH. The Ka for H2SO3 is 2.5 x 10^-3.
Kn = 2.5 x 10^11
What is the equilibrium constant expression for the Ksp of Ag2CrO4.
Ksp = [Ag+]^2+[CrO4-]
If there is a salt solution containing relatively the same concentration of sodium chloride and sodium iodide, which will form a precipitate first when silver nitrate is added? Explain why. Ksp for AgCl > AgI
NaI would precipitate as AgI because its Ksp is less than AgCl which means it will precipitate before AgCl/NaCl
Write the balanced net ionic equation for the naturalization reaction of H2SO3 with KOH. Calculate the value of Ka for H2SO3 is 1.0 x 10^-2.
Net equation: HF(aq) + NH3(aq) <--> NH4+(aq) + F-(aq) Kn = 7.68 x 10^5
Write the balanced net ionic equation for the naturalization reaction of HF and NH3. Calculate the value of Ka for the reaction when the Ka for HF is 2.4 x 10^-4 and the Kb for NH3 is 3.2 x 10^-5.
Net equation: HSO3(aq) + OH-(aq) <--> H2O(l) + HSO3-(aq) Kn = 1.0 x 10^12
Write and balance the neutralization reaction for Ca(OH)2 and H3PO4
OH- + H3PO4 <--> H2O + H2PO4-
The Ksp value for Ca(OH)2 is 1.50 x 10^-11. Calculate the concentration of Ca^2+
[Ca^2+] = 1.55 x 10^-4
Aspirin has a Ka of 3.98 x 10^-4. What is the ratio of A- to HA in: a. the blood (pH = 7.4) b. the stomach (pH = 1.4)
a. 10000 b. 0.01
A buffer initially contains 100 mL of 0.600 M HCO3- and 100 mL of 0.400 M CO3^2-. If the Ka for HCO3- is 1.23 x 10^-10, what is the initial pH? What is the pH after the addition of 0.0015 mol of HCl?
initial pH = 9.73 new pH = 9.71
Consider a solution initially containing 0.400 mol of F- and 0.300 mol of HF. What is the pH after the addition of 70 mL of 0.600 M HCl? (HF Ka = 7.20 x 10^-4)
pH = 3.16
The dissociation of acetic acid (CH3COOH) in an acetate ion (CH3CO2-) is given as follows. Calculate the pH of a buffer solution made from 0.25 M of CH3CO2H and 0.45 M of CH3CO2- when CH3CO2H has a Ka = 1.76 x 10^-5
pH = 5.0
Determine the pH of a solution prepared by dissolving 0.4 mole of NH4Cl in 1.0 L of 0.15 M aqueous NH3. The Kb of NH3 is 2.6 x 10^-6.
pH = 7.99
True or false: a larger Ksp value means greater solubility
true
Where is the equivalence point pH of a titration with a strong acid and strong base? a. pH = 9.2 b. pH = 5.0 c. pH = 7.0 d. pH = 2.3
C
Calculate the pH of the 0.2 M NH3/0.35 M NH4Cl buffer solution. The Kb for NH3 is 1.4 x 10^-6. What is the pH of the solution after the addition of 15 mL of 0.15 M HCl to 75 mL of the buffer?
pH = 7.91 pH = 7.80
Calculate the pH of the 0.4 M NH3/0.65 M NH4Cl buffer solution. The Kb for NH3 is 2.3 x 10^-6 What is the pH of the solution after the addition of 20 mL of 0.20 M HCl to 90 mL of the buffer?
pH = 8.16 pH = 8.08
Calculate the pH of a solution that contains 0.58 M of ammonia (NH3) and 0.43 M ammonium chloride (NH4Cl). (NH4+ Ka = 4.75 x 10^-9
pH = 8.45
Consider a solution initially containing 0.500 mol of ammonia and 0.300 mol of ammonium chloride. What is the pH after the addition of 40 mL of 0.800 M NaOH to the solution? (NH4+ Ka = 5.60 x 10^-10)
pH = 9.55
The pKa of a weak acid was determined by measuring the pH of a solution containing 0.35 M of the weak acid and 0.15 M of the conjugate base. If the recorded pH is 10.30, what is the pKa of the weak acid?
pKa = 10.67
Write the balanced net equations for the neutralization reaction: a. HI and NaOH b. HBrO3 and LiOH
a. H+(aq) + OH-(aq) <--> H2O(l) b. HBrO3(aq) + OH-(aq) <--> H2O(l) + BrO3-(aq)
How much HCl must be added to 1.0 L of buffer that is 0.8 M in acetic acid and 0.4 M sodium acetate to result in a buffer pH of 4.0? Acetic acid has a pKa of 4.62.
x = 0.167 mol
Answer the questions below about a titration of 250 mL of a 0.35 mL of a 0.35 M acetic acid (pKa = 4.76)(CH3COOH) with 0.35 M NaOH. a. volume of strong base to reach equivalence point b. volume at half equivalence point c. initial pH d. pH at half equivalence point e. pH at equivalence point f. draw the titration curve
a. 250 mL b. 125 mL c. 2.61 d. 4.76 e. 9.00 f. check paper
How many milliliters 0.45 M NaOH are needed to neutralize 75 mL of 0.15 M HCl?
25 mL
How many milliliters of 2.0 M KOH are necessary to neutralize 50 mL of 1.0 M HCl?
25 mL
Find the volume of 0.4 M NaOH at the equivalence point with 75 mL of 0.4 M HCl.
75 mL
Hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) to form sodium chloride (NaCl) and water. If delta H = -56.13 kJ/mol and delta S = 79.11 J/mol x K, what is delta G for this reaction at 20 degrees C?
delta G = -79.309 J/mol = -79.309 kJ/mol
Determine delta S for the reaction below given the following information. CO2 (g) + SF4 (g) --> CF4 (g) + SO2 (g) Substance S (J/mol x K) CF4 (g) = 261.6 SO2 (g) = 248.1 SF4 (g) = 299.6 CO2 (g) = 213.6
delta S = -3.5 J/K
