Buffers & pH

Titration

100

Equipment used to add the titrant in slow increments

Burette

200

The equivalence point.

What is The point in a titration at which the reaction between titrant and unknown has just been completed.

300

This is titrated to a weak acid to give an equivalance point pH greater than 7.

What is a strong base?

400

The buffer region on a titration curve is where?

What is the bottom flat part of the curve.

500

At the equivalence point of a weak acid–strong base titration, the solution’s pH is greater than 7 because this species undergoes hydrolysis.

What is the conjugate base?

Terms

100

This is an acid that does not fully dissociate.

What is a weak acid?

200

What is a BL Base?

A substance that receives a proton

300

Solutions that resist changes in pH when a strong acid or base is added

Buffer solution

400

This term that is used to describe a substance that is able to donate a hydrogen cation.

What is a Bronsted-Lowry acid?

500

This is what buffers are made of.

What is weak acid/base and it's conjugate?

Calculations

100

pH of a 0.01M HCl solution

[HCl]=0.01M

[H+]=0.01M

pH=-log(0.01)=2

200

pH of a 0.01M NaOH

[NaOH]=0.01 M

[OH-]=0.01M, pOH=-log(0.01)=2

pH=14-2=12 

300

pH of 0.005M HF Ka = 1.43x10-5

[H₃O⁺]=2.67×10⁻⁴

pH=-log(2.67×10^-4)=3.57

400

pH of 0.005M NH3 Kb = 1.43x10^-5

Kb=1.43×10⁻⁵=X²/(0.005−x)

X=2.67×10⁻⁴=[OH-]

pOH=-log(2.67x10-4)

pH=14-3.57

pH=10.43

500

Name this equation: pH=pKa + log([base]/[acid])

Henderson Hasselbach

Buffers

100

What does a buffer look like on a RICE table.

What is amounts of weak acid/base and its conjugate base/acid. 

200

You would add this to a solution of ammonia to make it a standard equation.

What is water?

300

This base would be used to form a buffer with HBr.

What is What is Br-?

400

This is the pH of 50.00 mL buffer solution which is 2.00M in HCl₂H₃O₂ and 2M in NaC₂H₃O₂. Ka of acetic acid=1.8x10^-5. Use HHE.

What is 4.74? pH = -log(1.85×10^-5) + log(2.00 / 2.00) pH = -log(1.85×10^-5) = 4.74

500

This is the pH for a solution of 1 mol ammonium and 1 mol ammonia when 36.5g of HCl is added . Ka of ammonium=5.9x10^-10

What is 4.61? 5.9×10^-10 = x²/1 [H+] = 2.4x10^-5 pH = -log(2.4×10^-5) pH = 4.61

Acids/Bases

100

The equation given is this: CH_3⁢CO₂H_{(𝑎⁢𝑞)}+H₂O_(𝑙)⇌H₃⁢O⁺⁡_{(𝑎⁢𝑞)}+CH₃⁢CO_2⁢⁻⁢_{(𝑎⁢𝑞)}

What K_w value do you use? K_a or K_b?

What is K_a?

200

Given the equation: NH₃⁢_{(𝑎⁢𝑞)}+H₂O_(𝑙)⇌NH_4⁢^+⁢_{(𝑎⁢𝑞)}+OH⁻⁢_{(𝑎⁢𝑞)}

What K_w do you use? K_a or K_b?

What is K_b?

300

Do all indicators change color at the same pH?

No

400

When does phenolphthalein turn pink?

When pH got above 7

500

What indicator turns blue at a pH of 11? 

What is Alizarin yellow