1. A comic book villain is holding you at gun point and is making you drink a sample of acid. She gives you a beaker with 100ml of a strong acid with pH=5. She also gives you a beaker of a strong base with a pH=10. You can add as much of the strong base to the strong acid as you want, and you must then drink the solution. You'd be best off trying to make the solution neutral before drinking it. How much of the base should you add?
2. Consider an exceptionally weak acid, HA, with a Ka = 1x10 -20 . You make a 0.1M solution of the salt Na
3. You have a powder that dissolves in water to form a strong acid. You dissolve 2g of the powder in 100ml of water, and measure the pH to be 4. You would like to form 100ml of a solution with pH 5. How many grams of the powder do you dissolve in 100ml of water?
4. You have two solutions, both with a concentration of 0.1M. Solution A contains a weak acid with a pKa of 5. ThepH of solution A is 3. Solution B contains a weak acid with a pKa of 9. The pH of solution B is:
5. You have 50 ml of a complex mixture of weak acids that contains some HF (pKa = 3.18) and some HCN (pKa = 9.21). Which is larger, [F-]/[HF] or [CN-]/[HCN]?
6. A mixture of 50ml of 0.1M HCOOH and 50ml of 0.05M NaOH is equivalent to:
7. I want to make a solution that will have [HCOO - ] = 3[HCOOH]. I start with 100ml of a 0.1M HCOOH solution. How many ml of a 1M KOH solution should I add?
8. Which do you think is a better buffer (more resistant to addition of acid and base)?
9. Consider a protein with the acidic side chains,
Amino Acid side-chain Arginine | pKa = 12.48 |
Aspartic Acid | PKa = 3.90 |
Cysteine | pKa = 8.33 |
Glutamic acid | pKa = 4.07 |
Histidine | pKa = 6.04 |
Lysine | pKa =10.79 |
Tyrosine | pKa =10.13 |
Given that the pH of blood is about 7.3, how many of the above side chains would be mostly in their ionic form (A-) in blood?
Problem 10
You are titrating an acid with a pKa of 7. You are given a choice of indicators with the following pKa's, which do you use?
11. CO2 dissolves in water to form carbonic acid: H2CO3 <---> H+ + HCO3-Ka1 = 4.3 x l0-7 HCO3- <---> H+ + CO3-2 Ka2 = 4.8 x l0-11 In an acid solution with pH =4.35 ([H+ ]=4.5x10-5), what is the ratio [CO3-2] /[H2CO3]?
1. A comic book villain is holding you at gun point and is making you drink...
A comic book villain is holding you at gun point and is making you drink a sample of acid. She gives you a beaker with 100ml of a strong acid with pH=5. She also gives you a beaker of a strong base with a pH=10. You can add as much of the strong base to the strong acid as you want, and you must then drink the solution. You'd be best off trying to make the solution neutral before drinking...
A buffer solution is made by adding 10 mL of 2M NaOH to 50mL of a weak acid HA. The pKa of HA is 3.42, and the activity coefficient of the weak acid is 1.6 and the activity coefficient of the weak base is 0.75. If the pH of the resulting solution is 4.59, what was the concentration of the original HA solution?
as A Questions 1-4 refers to the five titration curves (labelled mL of titrant mL of titrant ml of titrant mL of titrant mL of titrant 1 Which curve shows the titration of a strong acid with a strong base? AA BB CC DD EE Fnone of the above 2 Which curve shows the titration of a weak acid with a strong base? A A BB CC DD EE Fnone of the above 3 Which curve shows the titration of...
help with these chemistry questions 1. Explain what happens to the concentration of H,O' ions in an acetic acid solution when solid sodium acetate is added. 2. Determine the pH and pH of a solution that is 0.5 M NaHSO4 and 0.25 M Na2SO4 3. When sodium nitrite is added to HNO2(aq) a) the equilibrium concentration of HCOOH(aq) decreases. b) the pH of the solution increases. c) the K increases. d) the pH of the solution does not change. e)...
If anyone could kindly explain how to do these.... Any help is appreciated with the following problems!! Thanks in advance Case study: HA with a pKa = 5.0 (i.e. Ka = 10 -5) Class 1 acid (HA) only What is the pH of a 0.01 M solution of this weak acid HA? [HA] = 10 -2, >> Ka =10 -5) Class 2 base (A-) only What is the pH of a 0.01 M solution of NaA? Class 3 acid &...
You have a powder that dissolves in water to form a strong acid. You dissolve 2g of the powder in 100ml of water, and measure the pH to be 4. You would like to form 100ml of a solution with pH 5. How many grams of the powder do you dissolve in 100ml of water? 0.2 g 0.4 g 20 g 40 g
Consider weak monoprotic acid HA(aq) D H+(aq) + A–(aq) with Ka = 4.0 x 10–5 and pKa = 4.40. A solution is composed of 900.0 mL of 0.090 M HA and 0.080 M NaA (10 points). (a) Calculate the pH of this solution. (b) Calculate the pH of the above solution following the addition of 10.00 mL of 2.0 M NaOH (a strong base).
What is the pH of an acidic mixture containing 0.005 M HBr and 0.025M HCN? HINT: take into account the type of acids that make up the mixture. Which solution is the least acidic? A. 3.0 M HNO3 B. 3.0 M HI C. 3.0 M HClO D. 2.0 M HCN and 2.0 M HF Calculate the pH of a basic solution made from 255 mg of pyridine (C5H5N) dissolved in 1L of water. The pKb for pyridine is 4.2. Determine...
You work in a chemistry lab, and are asked to prepare 500 mL of a buffer solution with pH-3.20, The weak acid solution concentration in this buffer should be 0.250 M and salt is a solid. The following steps walk you through a step by step process of this preparation. a. Choose the proper weak acids for the buffer solution Table 1. Ionization constant Ka for some weak acids Name Hydrofluoric acid Nitrous acid Fulminic acid Acetic acid Hypochlorous acid...
Lab 5 Buffers 1. Dissolved ions in salt solutions can act as acids or bases and react with water to produce hydronium ions or hydroxide ions that contribute to the pH of the salt solution. Since strong acids and strong bases completely ionize in solution, the reverse reaction essentially does not occur, meaning that the resulting conjugate base of a strong acid or conjugate acid of a strong base do NOT act as acids or bases. Ions that are conjugate...