Acids Definition and 187 Threads

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...

Checked google no satifying answer.Thanks :smile:

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...

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?

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:

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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

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...

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...

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.

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!

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)?

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?

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...

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...

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...

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...

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...

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...

[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.

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...

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...

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

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 =...

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.

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...

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... ...

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...

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

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...

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...

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?

"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

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...

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...

-------------------------------------------------------------------------------- Hi there When talking about limiting amino acids what does it really mean... What I think it means is say we have a food eg wheat it has all the essential amino acids (aa) in it except one of them is not...

could the equation - pH=pKa+log([A]/[HA]) - be applied for the case of strong acid? Although the percentage of dissociation of strong acid/base is very high, there still exists a equilibrium, right? secondly, if i tried to explain the resistance in pH of buffer *in terms of* the above...

I am a little stuck on this question : Solution A contains n moles of a weak acid HX. The addition of some sodium hydroxide to A neutralises one third of the HX present to produce Solution B. In terms of the amount, n how many moles of HX are present in Solution B? I think there are one...

Hi, I am starting to get desperate with my search to find information about the reaction of plastics with acids. I have searched all over the internet for a while now and I have found very little. If anyone knows anything about the form of any reactions that take place with plastics and acids...

I got my test back and one of the questions was the following Which is a property of a saturated fatty acid? (a) no double bonds (b) (c) rubbish (d) maximum number of single bonds I answered (d), but the professor says it's (a). I don't think it's (a) for two reasons-- a pi double...