Acids/Bases
Buffers/pH
Titration & pH
Thermodynamics
100

Acids are what? What do they produce?

Hydrogen ions/protons, electron acceptors

100

A 1.0L buffer solution is 0.10 M in HF and 0.050 M in NaF. Which action will destroy the buffer?

a) adding 0.050 mol of HCl

b) adding 0.050 mol of NaF

c) adding 0.050 mol of NaOH

100

Part 1: A 50 mL sample of 0.200M NaOH is titrated with 0.200M nitric acid. What are the moles of HNO3?

0.00600 mol HNO3

100

Which has a greater entropy?

1a) Solid CO2 or gaseous CO2

2a) N2 gas at 1 atm or N2 gas at 1.02*10^-2 atm

1a) Gaseous CO2

2a) gas at 1.02*10^-2 atm

200

Bases produce Hydroxide ion and are __

electron donors/Nucleophiles

200

This curve represents 

titration of a strong acid/strong base curve.

200

Part 2: A 50 mL sample of 0.200M NaOH is titrated with 0.200M nitric acid. What is the pH after adding 30 mL of HNO3?

12.70

200

Second Law of Thermodynamics

in any spontaneous process, there is always an increase in the entropy of the universe

300

Common Ion Effect: In which solution is BaSO4 most soluble?

a) In a solution that is 0.10 M in BaNO3

b) In a solution that is 0.10 M in Na2SO4

c) In a solution that is 0.10 M in NaNO3

300

A chemist needs a solution buffered at 4.30 pH and can choose from the following:

a) propanoic acid Ka=1.35*10^-5 [HA]/[A]=3.8

b) benzoic acid Ka=6.4*10^-5  [HA]/[A]=.78

c)hypochlorous acid Ka=3.5*10^-8 [HA]/[A]=1.4*10^3

Benzoic acid

300

Hydrogen Cyanide gas HCN is a powerful respiratory inhibitor with a Ka of 6.2*10^-10 when dissolved in water. If a 50 mL sample of 0.100 M HCN is titrated with 0.100M NaOH, calculate the pH of the solution at the halfway point.

9.21

300


Exothermic- spontaneous(energy release)

400

Calculate the pH of a solution containing 0.75M lactic acid Ka=1.4*10^-4 and 0.25M sodium lactate.

3.38

400

A buffer solution contains 0.50 M Acetic Acid Ka=1.8*10^-5. Calculate pH when 0.0100 moles of solid NaOH is added to 1.0L of the buffered solution.

4.76

400

Hydrogen Cyanide gas HCN is a powerful respiratory inhibitor with a Ka of 6.2*10^-10 when dissolved in water. If a 50 mL sample of 0.100 M HCN is titrated with 0.100M NaOH, calculate the pH of the solution after 8.00 mL of 0.100 M NaOH has been added.

8.49

400

When delta S is zero...

System is at equilibrium, no tendency to occur

500

In a solution of H+ in a 1.0 M HF solution is 2.7*10^-2 M and the percent dissociation is 2.7%. Calculate [H] & percent dissociation of HF. Ka=7.2*10^-4 [NaF] is 1.0M.

[H]=7.2*10^-4 M and 0.072%

500
A buffer contains the weak acid HA and its conjugate base A. The weak acid has a pKa of 4.82 and the buffer has a pH of 4.25. Which statement is true of the relative concentrations of the weak acid and conjugate base in the buffer?

a) [HA]>[A]

b) [HA]<[A]

c) [HA]=[A]

500
Hydrogen Cyanide gas HCN is a powerful respiratory inhibitor with a Ka of 6.2*10^-10 when dissolved in water. If a 50 mL sample of 0.100 M HCN is titrated with 0.100M NaOH, calculate the pH of the solution at the equivalence point.

10.96

500

Calculate delta G @25C for the synthesis of methanol, where carbon monoxide gas at 5 atm and hydrogen gas at 3 atm is converted to liquid methanol. delta G for H2=0kJ, methanol is -166kJ, and carbon monoxide is -137kJ

-38kJ/mol