Acids Definition and 194 Threads

  1. T

    Test for amino acids in Protein shakes (Experiment)

    I was wondering whether anyone knows an experiment relating to bodybuilding protein shakes. I want to find out which amino acids are present within the protein shake by doing an experiment but i have no clue what how to carry it out. The protein is in powder form. I was thinking of...
  2. K

    What is the relative size of amino acid R chains and how can it be determined?

    I need to compare amino acid R chains relative to each other. Is there a way to figure this out with the chemical forumula or am i supposed to glance over the stuctures? Also I am finding mixed messages about polarity for each. Are these correct? thanks lab test rf...
  3. K

    Estimating Volumes of Amino Acids in nm^3

    Homework Statement Estimate the volumes of the various amino acids in units of nm^3 Homework Equations V = 4/3*pi*r^3 The Attempt at a Solution Is it alright to treat the amino acids as spheres? Using this I was thinking of measuring the distance, atomic radii and bond length...
  4. S

    What Does 2-Amino-Propanol Formation Indicate About an Octapeptide's Structure?

    Homework Statement A small octapeptide was isolated. Amino acid analysis from 6N HCl hydrolysis indicated: 14 micromoles alanine, 17 micromoles ammonium, 15 micromoles valine, 16 micromoles arginine, 46 micromoles of isoleucine, 15 micromoles of glycine, 17 micromoles of aspartate...
  5. H

    PCB Fabrication at Home: Basics & Acids Needed

    Hello, am trying to make pcb at my home, but am not sure about the sequence of fabrication steps. i put the board in UV light for several minutes, then i put it in a basic solution and finally in ana acidic one, but nothing happened to my board... What are the names of bases and acids used for...
  6. P

    Transforming Penicillin G Salts to Acids

    Hi all, I need some help! some info: Penicillic acid [CAS RN: 90-65-3]: an antibiotic substance produced by several species of Penicillium and Aspergillus Penicillin G: Used in medicine. It is used in the form of its stable salts (benzathine, potassium, procaine, and sodium) Penicillin G...
  7. S

    Do essential amino acids undergo transamination reactions?

    Checked google no satifying answer.Thanks :smile:
  8. S

    How are non essential amino acids synthesized?

    Hello everyone, My biochemistry book just says there are 20 amino acids that are essential and not synthesizd by the body. Then it doesn't say how other amino acids are synthesized. My guess is they are synthesized from transamination reactions of essential amino acids. Does that mean if you...
  9. B

    Can monoprotic acids produce a greater pH change than diprotic acids?

    Sulphuric acid is a diprotic acid that dissociates completely when dissolved in water. How does a monoprotic acid like trifluoromethanesulfonic acid produce a greater pH change than H2SO4?
  10. S

    Why do radicals attack polyunsaturated fatty acids?

    Is it because they are unsaturated and can unfold. I understand how one radical would create another radical but I don't know exactly how radical could spread in a fatty acid chain. Any diagram would be useful. Thank you :smile:
  11. I

    Resistance versus temperature in weak acids, strong acids, and water

    The question below is a rather theoretical one and does not concern any actual calculations. So I have decided to abandon the traditional format. In the past few weeks, I have designed and carried out a lab in which I would test the resistance of a strong acid (0.5 M HCl), a weak acid (0.5 M...
  12. N

    PH concentrations, strong acids and water

    Hello! I was wondering, with questions such as "What is the pH of 0.05 mol dm-3 of HCl?", you specify the pH by simply using the concentration, as it completely dissociates. However, I assume that at such a concentration like this it is not 'pure', and would be present in water. Shouldn't I...
  13. J

    Affect of adjacent amino acids on pKa values

    Hello, I use some standard tables of amino acids pKa values, as the one here: http://www.cem.msu.edu/~cem252/sp97/ch24/ch24aa.html and I am especially interested in the pKr (i.e. pKa of the side chains). Correct me if I'm wrong, but pKa values listed in such tables refer to a "free" peptide...
  14. W

    Mixtures of Acids and Bases: What Type of Solution is Produced?

    Homework Statement You prepared a reaction table for 10.0 mL of 0.1 M NH4Cl with 5.0 mL of 0.1 M NaOH. Please choose all of the following that describe the solution that was produced. The choices are: 1. a solution containing only a strong base 2. a solution containing a weak acid and a...
  15. P

    Which Acid Is Stronger, HA or HB?

    Homework Statement Acid HA has a pKa=20; acid HB has a pKa=10 a. which is the stronger acid? b. will an acid-base reaction with an equilibrium lying to the right take place if Na+ A- is added to HB? Explain your answer. Homework Equations The Attempt at a Solution I know that...
  16. S

    Reactions of Barium Chromate with Acids: Different Results?

    Hi guys today in the lab i did reaction of barium chromate with hydrochloric acid and when i add HCL to barium chromate i got a reddish orange solution but when i add sulphuric acid i got a colorless solution with yellow ppt. Why is this so? Shouldn't both give me the same result since they are...
  17. C

    Using indicators to determine acids, bases, and salts

    Hey, I just got out of my lab at school and just realized that me and my professor made a mistake. He marked my lab complete, and I also thought it was complete, however, I just realized that there was something missing. The problem is that I can't go back into the lab to try it out again...
  18. J

    Exploring Acids & Bases: Sodium Acetate & Cyanide Solutions

    Here's the question: And the answer is: Which makes sense to me, because acetic acid is the stronger acid. But there's another option in the list that it says is NOT true: I thought this might be true, because both are solutions of chemicals that were referred to as acids. Am I...
  19. T

    Essential Fatty Acids: Nutrients in USDA Database

    For a program I'm writing (which is supposed to create a balanced meal), I'm using two pieces of information: USDA's dietary reference intakes and a database (also from them) of nutrients each food product contains. There is a problem, though: the nutrients listed by the DRIs don't have a 1 to 1...
  20. L

    Dissociation Constant of Weak Acids

    Homework Statement In my lab, it says that i have to calculate the pH and the Ka of an unknown acid of known concentration (0.20 mol/L)..however, the part that is confusing me is that we first had to obtain 40 mL of that particular unknown acid... Homework Equations The Attempt at a...
  21. L

    How to Calculate Species Concentrations in a 0.010 M Solution of NaN3?

    Homework Statement Soldium azide, NaN3 is sometimes added to water to kill bacteria. Calculate the concentration of all species in a 0.010 M solution of NaN3. The Ka value for hydrazoic acid, HN3 is 1.9X10^-5. Homework Equations The Attempt at a Solution I'm sort of confused because...
  22. L

    Differentiating Acids and Bases Based on Chemical Formulas

    Homework Statement does anyone know how i can differentiate a strong acid from a weak acid and likewise for a strong base and a weak base based on its chemical formula? Homework Equations The Attempt at a Solution
  23. Y

    Understanding Acids What is the relationship between Ka and Kw?

    I'm not sure if this belongs in the HW section but I'm not doing HW so I'll post it here. My book mentions the auto-ionization constant of water( Kw = [H+][OH-] = 1.0 E-7 ) and shows us how we can use it to find the pH if a strong base is added by solving for [H+]. Later on in the book it...
  24. M

    Illustrate Hydrogen Bonding: Amino Acids

    Homework Statement The following structures illustrate hydrogen bonding interactions between amino acid side chains and/or backbone atoms within a protein structure. In which of the following figures are the structures and hydrogen bonding completely correct? Homework Equations...
  25. S

    Why Is HCl a Stronger Acid Than H2S?

    Explain the following observations a) HCl is a stronger acid than H2S; etc... I just need to know how to find this out, I read through the chapter but it didn't explain it all that well, and the notes my teacher gave me didn't go over it at all.
  26. S

    Struggling with Acids and Bases Concepts in Chemistry AP?

    I was looking for information in regard to Acids and Bases. I'm having a awful time with conceptual questions concerning this chapter in class, and I'm getting pretty frustrated. Any practice questions / supplemental in depth tutorials would be nice. Thanks!
  27. A

    Organic Chem: Benedict's test and acids - false positives?

    Since Benedict's test is testing for the presence of a reducing agent (in the form of a carbohydrate), would that not mean it would give a false positive if acid was present (i.e. is acid not considered to be a reducing agent, it being a proton donor)?
  28. W

    What mechanism is responsible for the sequencing of amino acids?

    Homework Statement What mechanism is responsible for the sequencing of amino acids? Homework Equations The Attempt at a Solution I don't quite understand, is it asking what is the procedure called that causes sequencing of amino acids?
  29. 3

    What is the pH of a Mixture of 2.00M Chlorus Acid and 2.00M Formic Acid?

    Homework Statement 2.00M chlorus acid and 2.00M formic acid are mixed. What is the pH? Homework Equations Ka of chlorus acid is 1.1×10-2 Ka of formic acid is 1.78×10-4 The Attempt at a Solution For chlorus acid with quadratic equation to find x: x²+0.011x-0.022...
  30. D

    Experimenting with Acids & Bases: DeltaH, Dissociation & Bond Strength

    I did an experiment with a) strong acid (HCl) and strong base (NaOH) b) weak acid (ethanoic) and strong base (NaOH) so, I am looking at the heat of energy for both the reactions, and so i found that reaction a had a greater heat of energy was that of the reaction b) weak acid and...
  31. D

    Bronsted - Lowry Theory Of Acids and Bases

    Homework Statement Some of the books I have state that the equation of... HCl + NH3 --> NH4+ + Cl- While others state that the above equation should be written as... HCl + NH3 --> NH4Cl Which one is correct? I think the answer should be the second one since the two compounds...
  32. T

    Bacteria vs Acids: Sugar's Role in Sanitizing

    Why is it that a cutting board smeared with lunch meat can be sanitized by weaker acids better than the stronger acids? (weaker acids as in vinegar/grapefruit juice) (stronger acids as in lemon juice/lime juice) Grapefruit has more sugar than lemon or lime. So, can I assume that sugar has...
  33. N

    Why do some salts react with acids while others don't?

    I am new to the concepts of reaction between of Acids, Bases and Salts. While learning, I notice that some salts react with acids to form a new salt (and sometimes a new acid is produced), especially in Qualitative Analysis, while some don't even reacts. I tried to search the internet about it...
  34. C

    Determining the Most Effective Buffer Solution for pH Stability

    Hi there I was wondering if anyone could help me with this buffers question ... For which of these liquids is the pH likely to change least if a splash of concentrated sulphuric acid is added? Justify your answer: a) 0.1M hydrochloric acid solution b) 0.08M ethanoic acid/0.02M potassium...
  35. X

    Acids, Bases, and Salts: Essential Equations and Laws for Success in Class

    [SOLVED] Acids, Bases, and Salts I will be starting on a new chapter unit of Acids, Bases, and Salts for class. I was wondering what important information I should be aware of, like equations and laws since I want to stay ahead of my class, and not die if I miss a day.
  36. J

    How Much Sodium Bicitrate Is Required for a pH 5.42 Solution?

    Homework Statement What mass of sodium bicitrate would be needed to prepare a 1.00 L solution with a pH of 5.42? Homework Equations [H30+]=10^-pH The Attempt at a Solution First of all, I don't know what sodium bicitrate is, so I can't write the equation for it. What's bicitrate...
  37. T

    Effects of heating up different fat acids

    Hello! The question about which oil that is the best to fry in, or to deep-fry in, should be examined, if it hasn't been already. Is it possible to set up a function b_f(T), where b is the "badness" of heating up a certain kind of fat f to temperture T? For example, saturated fat can be...
  38. M

    Left Handed Amino Acids Discovered in 4.5x10^9 year old metorite

    http://www.sciencedaily.com/releases/2008/02/080228174823.htm This seems exciting for origin of life research.
  39. A

    Chemistry - acids, bases, equilibrium

    Homework Statement Like all equilibrium constants, Kw varies somewhat with temperature. Given that Kw is 3.49e-13 at some temperature, compute the pH of a neutral aqueous solution at that temperature. Homework Equations Kw = [H+][OH-] pH = -log[H+] The Attempt at a Solution 3.49e-13 =...
  40. K

    Which of these methods can break ionic bonds between amino acids?

    i am doing revision for my exams aand was wondering which one of these, high temperature, hydrolysis or pH change would break the ionic bond between amino acids. I would go for pH change. I have no reason, it's just instinctively.
  41. D

    Comparing Acids: H_2 C_2 O_4 & H_3 O^+

    Using the following reaction for example: H_2 C_2 O_4 _{(aq)} + H_2 O_{(l)} \to HC_2 O_4 ^ - _{(aq)} + H_3 O^ + _{(aq)} The question asks to predict weather the reaction will occur to a large or small extent. What i would usually do is decide weather the H_2 C_2 O_4 or the...
  42. E

    Ranking Lewis Acids: Weak to Strong - Resources & Tables

    Hello, Just wondering if anyone could post some resources on lewis acids: ie weak to strong lewis acid ranking or maybe some table or chart of lewis acids and their reactivity I haven't been able to find any resources thus far regarding lewis acids and their reactivity rankings... ...
  43. J

    How Is the Acidity or Basicity of Amino Acids Determined?

    How can you tell if a given amino acid is acidic or basic? I'm lost here. My first thought would be to look at the pKa values. There is virtually no difference in the pKa values for the carboxyl groups; all range from 1.82-2.38. The same goes for the pKa values of the amino groups; all range...
  44. R

    Can Excessive Consumption of Amino Acids Lead to Disease?

    Is it okay to eat pure amino acids or can they cause disease?
  45. I

    Identifying Lewis Acids: H3O+, Cl-, SO2, and GaCl3 | Homework Solution

    Homework Statement Which of the following reactants are lewis acids? H3O+ + N2H4 --> N2H5+ + H2O Ag+ + Cl- --> AgCl CaO + SO2 --> CaSO3 GaCl3 + Cl- --> GaCl4 Homework Equations Lewis acids are electron pair acceptors while lewis...
  46. P

    I have my acids and bases test tomorrow, and i with a few types of problems

    im looking at some review problems my teacher gave me today, and i can pretty much do most of them. however, there is this one i really have no idea what to do. Its a 2 part problem. 1a.What is the pH of a 1000 ml of a 0.1 M acetic acid solution, given pKa = 4.8? 1b. what is the pH of...
  47. J

    Calculate the pH of 100mL HOAc + 100mL Ba(OH)2

    Homework Statement find the pH of: 100mL x .20M HOAc + 100mL x.10M Ba(OH)2 The Attempt at a Solution 100x.2 = 20mmol HOAc 100x.1 = 10mmol Ba(OH)2 20-10=10 10/200=.05M pOH = -log(.05) = 1.3 pH=14-1.3=12.7 Is this correct?
  48. B

    Dissolving Weak Acids: What to Expect with 0.5g Sodium Acetate in Water

    "If 0.5g of sodium acetate is dissolved in water, what would you expect to find in the resulting solution"? Is it acetic acid, acetate, or hydroxide? I don't know how to set this one up
  49. L

    Understanding Bronsted Acids and Bases: Classification and Examples

    Anyone clever with bronsted acids and bases? I'm pretty new in chemistry, but I'm trying to learn. Right now I'm suppose to classify some species as either bronsted acids or bases, or even both. For example 1. Water 2. OH- 3. NH4+ 4. HCN 5. HBr 6. NH3 Hope someone can help...
  50. J

    Kinetics of metals reacting with acids

    hey. I am doing an investigation into reactions of acids with Mg. Firstly, iv investigated how order with respect to the acid varies for different acids i found that the orders for each of the acids are: Hydrochloric acid: 2 Sulphuric acid: 1 Phosphoric acid: 1.8 in an article, it said that...
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