2 Chem, 2 Midterm

True or False

100

A strong acid, when mixed with water, will retain its structure.

False, it dissociates completley

200

Buffers can be made from strong acids and bases.

False. 

300

Any buffer maintains a solution's pH across all ranges of pH.

False

400

Lewis bases furnish H+ ions in a solution.

False.

500

A stronger weak acid had a lower pKa than a weaker weak acid. 

True. 

Acids and Bases

100

Define a Lewis acid.

Acid that accepts electron pairs.

200

What type of salt is NH4NO3 when hydrolyzed?

Acidic, basic, or neutral?

Acidic. 

300

What is the conjugate acid of H2PO4-?

A) H3PO4 

B)PO4

C)HPO4^2-

D)H3PO4+

A)H3PO4

Bonus: What is the conjugate base?

400

Identify the Bronstead-Lowry acids in this equation:

HS- + SO4^2- <-> S^2- + HSO4- 

HS- and HSO4-

500

Consider the following equilibrium system:

OCl- + HC7H5O2 <-> HOCl + C7H5O2- 

Keq=2.1 x 10^3

At equilibrium, which direction is favored?

What is the stronger acid?

Products are favored.

HC7H5O2 is the stronger acid.

A high Keq creates more stable conjugate bases

pH

100

Does an Arrehius acid have a low or high pH?

Low pH.

200

What is the relationship between H₃O+ and pH?

Inverse relationship. if pH is low, H₃O+ is high. 

300

If a student were making a buffer and a small amount of base is added to that buffer, what happens to the pH? 

It stays relatively constant. 

400

The pH of an aqueous solution is 4.32. What is the OH-?

2.1 x 10^-10 [M]

500

Calculate the pH of 2M solution of nitrous acid (HNO₂) in water. Ka of HNO₂ = 4.0 x 10^-4.

1.54

Miscellanious

100

What is the relationship of pKa to pH?

pH +/- 1 = pKa

200

Explain buffers to a 6-year-old. 

?

300

What does RICE stand for?

Reaction, Initial, Change, Equilibrium

400

Between triflurocetic acid (CF₃COOH) and Acetic acid (CH₃COOH), which is the stronger acid?

Triflurocetic acid 

Has an I- effect, as the three fluorine have greater electronegativity than hydrogen.

The conjugate base is more stable (content)

500

Arrange the acids in order of increasing strength:

Acid A: pKa= 1.52

Acid B: pKa= 6.93

Acid C: pKa= 3.86

B, C, A

Potpourri

100

What should I bring to the exam?

Calculator, Periodic table, Pencil, Index Card (5x3), Can-Do attitude, some water. 

200

Who won The Master's Tournament yesterday, becoming only the 6th player to ever complete a career grand slam of The Masters, The Open, The PGA championship, and the US Open?

Rory Mcilroy.

Bonus: What sport is this?

300

What are not allowed to have on your index card?

Practice problems and answers.

Anything Wesley might consider suspicious. 

400

What is one thing you'll put on your index card?

Provide a valid example!

500

Coming up in May, this "greatest spectical" was once run on a full brick oval. Now just three feet wide, these bricks give the track its iconic nickname, The Brickyard.

What is the Indianapolis 500?