An acid is a molecule or ion capable of either donating a proton (i.e., hydrogen ion, H+), known as a Brønsted–Lowry acid, or, capable of forming a covalent bond with an electron pair, known as a Lewis acid.The first category of acids are the proton donors, or Brønsted–Lowry acids. In the special case of aqueous solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents. A Brønsted or Arrhenius acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H+.
Aqueous Arrhenius acids have characteristic properties which provide a practical description of an acid. Acids form aqueous solutions with a sour taste, can turn blue litmus red, and react with bases and certain metals (like calcium) to form salts. The word acid is derived from the Latin acidus/acēre, meaning 'sour'. An aqueous solution of an acid has a pH less than 7 and is colloquially also referred to as "acid" (as in "dissolved in acid"), while the strict definition refers only to the solute. A lower pH means a higher acidity, and thus a higher concentration of positive hydrogen ions in the solution. Chemicals or substances having the property of an acid are said to be acidic.
Common aqueous acids include hydrochloric acid (a solution of hydrogen chloride which is found in gastric acid in the stomach and activates digestive enzymes), acetic acid (vinegar is a dilute aqueous solution of this liquid), sulfuric acid (used in car batteries), and citric acid (found in citrus fruits). As these examples show, acids (in the colloquial sense) can be solutions or pure substances, and can be derived from acids (in the strict sense) that are solids, liquids, or gases. Strong acids and some concentrated weak acids are corrosive, but there are exceptions such as carboranes and boric acid.
The second category of acids are Lewis acids, which form a covalent bond with an electron pair. An example is boron trifluoride (BF3), whose boron atom has a vacant orbital which can form a covalent bond by sharing a lone pair of electrons on an atom in a base, for example the nitrogen atom in ammonia (NH3). Lewis considered this as a generalization of the Brønsted definition, so that an acid is a chemical species that accepts electron pairs either directly or by releasing protons (H+) into the solution, which then accept electron pairs. However, hydrogen chloride, acetic acid, and most other Brønsted–Lowry acids cannot form a covalent bond with an electron pair and are therefore not Lewis acids. Conversely, many Lewis acids are not Arrhenius or Brønsted–Lowry acids. In modern terminology, an acid is implicitly a Brønsted acid and not a Lewis acid, since chemists almost always refer to a Lewis acid explicitly as a Lewis acid.
"By taking a little apple cider vinegar before a meal, you can increase stomach acidity and thereby improve digestion and nutrient uptake. "
But since vinegar is less acidic than stomach acid wouldn't it follow that vinegar would reduce stomach pH? (unless the watery contents of vinegar flux...
Procedure:
1. Pipette 25 cm3 of ethanoic acid into a conical flask
2. Titrate against 0.1M sodium hydroxide solution in the burrette, using phenolphthalein as indicator.
3. Pipette further 25 cm3 of ethanoic acid into the solution after titration and mix throughly.
Questions:
1. what is...
I currently have a set up where I have attached a permanant magnet dc motor to a bicycle. The motor is attached through a diode to a 12v regulator and then to a 12v to 240v inverter. Everything works fine and I can power up my devices.
But I have been told that if I connect my 12V lead acid...
OK, so I just got out of an organic chemistry exam. I feel pretty good about every question except one which I did not know - please help me put my mind at ease!
What is the major product of the reaction of this molecule:
http://img216.imageshack.us/my.php?image=stupidthingdw3.jpg
with...
Homework Statement
Titrating .1006M CH3COOH with .2012M NaOH. pKa=4.74, Ka=1.8*10^-5
What is the pH at the equivalence point of the titration?
Homework Equations
pKa = -log(Ka) pH = -log[H+]
The Attempt at a Solution
Alright, after setting up an ICE table (in order to find...
I'm having some trouble understanding what happens when Zinc and Hydrochloric acid are reacted with Copper Sulfate as a catalyst. I *think* the Copper ion gets electrons from the zinc and turns into straight copper which leaves zinc free to react with the chlorine to form zinc chloride. Does...
Why is the enthalpy of neutralisation of a strong acid mixed with a strong base always the same, no matter what acid and base combination you use, provided they are 'strong' acids and bases?
Am I right to say that this value is accepted as -57.35 kJmol-1?
Thanks for any help,
Isaac.
hi
i have the following reaction
isobutyric acid + 2-methoxyethanol <-> 2-methoxyethyl-2-methylpropanoate
but i don't know all of the by-products.
please help thanks
edit: i think is only water and some unreacted reactants?
Homework Statement
If Lovastatin were heated in dilute aqueous acid, what would the molecular weight of the product be? (The large of the two products. Assume that there is no hydration of the alkene functionalities.)
Homework Equations
N/A
The Attempt at a Solution
I drew...
Homework Statement
Stearic acid, nature's most common fatty acid, dimerizes when dissolved in hexane:
2C17H35COOH --> (C17H35COOH)2 H°rxn = -172 kJ
The equilibrium constant for this reaction at 28°C is 2900. Estimate the equilibrium constant at 38°C.
1) 4.7 *10^5
2) 1.9 * 10^3...
Homework Statement
A buffer is prepared by dissolving 1.00 mole HLac (with a ka=8.0x10-3) and 1.00 mole of sodium lactate (NaLac) in enough water to form one (1) liter of solution. Calculate the [H+] and the pH of the buffer.
36 minutes ago - 3 days left to answer.
Additional Details
12...
[SOLVED] Titration Lab
Homework Statement
How many grams of pure citric acid in the juice solution when 4.00 g of the juice crystals are dissolved in 100.0 mL solution?
The juice solution is titrated using a given solution of sodium hydroxide. The NaOH is titrated into 10 mL of the juice...
I have to examine the amino acid sequences of a segment of each of the following proteins: lysine, alanine, leucine, arginine, isoleucine, proline, glycine, histidine, and serine. Provide, in order, a list of the following potential components.
a. tRNA nucleotides (in the anticodon loop) that...
[b]1. The dipole moment of a peptide bond is 3.7 Debye in water. Assuming that a hydrogen bond is essentially a dipole-dipole interaction, estimate the energy of a hydrogen bond between two peptides in water and in the interior of a protein (neglect the competing interactions with the solvent)...
Homework Statement
How does sulphuric acid catalyze the preperation of ester?
The Attempt at a Solution
Does it cleave the molecule that becomes the ester?
Homework Statement
We did a lab in class about weak acid/strong base titration, but I'm having a bit of trouble. We we only given the molarities of an unknown weak acid and a strong base (NaOH) and the pH of six different mixtures containing different mL of the two, which is below:
Test...
Can a solution of 35% sulfuric acid and 65% water be safely stored in a plastic bottle? That is, does sulfuric acid of this concentration react with any or all plastics? if plastic is not acceptable, what type of storing container could safely contain the acid?
If interested, what I have in...
Homework Statement
A beaker with 135 mL of an acetic acid buffer with a pH of 5.00 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.1 M. A student adds 7.80 mL of a 0.400 M solution to the beaker. How much will the pH change? The pKa of acetic acid...
A beaker with 135 mL of an acetic acid buffer with a pH of 5.00 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.1 M. A student adds 7.80 mL of a 0.400 M solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.76.
What I did...
Hi
I have been trying several days to solve this problem. But i can't find the procedure to solve this weak acid and weak base problem. I will really appreciate some help.
What is the pH of a soft drink in which the major buffer ingredients are 6.90 g of NaH2PO4 and 5.70 g of Na2HPO4 per...
Hi
I have been trying several days to solve this problem. But i can't find the procedure to solve this weak acid and weak base problem. I will really appreciate some help.
What is the pH of a soft drink in which the major buffer ingredients are 6.90 g of NaH2PO4 and 5.70 g of Na2HPO4 per...
Homework Statement
A solution is to be buffer at pH = 3:35 with formic acid and formate.
(a) How many moles of formic acid and sodium formate are needed if the solution is to change pH by < 0:02
for the addition of 0.02 moles of strong acid?
i need help how to set up a problem like...
[SOLVED] magnesium and acid rates reactions
im producing an investigation in the reaction between magnesium a solid metal, and acids of varying concentration, pH and temperatures. these variables are to produce results for comparison. however i am unsure about what apparatus would be most...
Homework Statement
A 0.307g sample of an unknown triprotic acid is titrated to its equivilence point using 35.2ml of 0.106 M NaOH. Calculate the molar mass of the acid. Answer is in g/mole.
Homework Equations
The Attempt at a Solution
I just don't know where to start with this...
Homework Statement
I've been working on this problem and am having issues with some of the problems...
all we learned was that EQ is pH= pka and at eq and EQ1/2 is pk1+pk2/2 which can't even be applied to this question due to x values.
I would GREATLY appreciate ANY help/guidance/etc...
25 mL of 0.1 M HOAc are titrated with 0.15 M NaOH. What is the pH at
equivalence?
I know that the pH at start will be greater than 1.0 and the pH at equivalence will be greater than 7 since its a titration of a weak acid and a strong base. But what I don't know is whether or not there is a...
Hey Guys, I seem to be having some problem with this question. Can anybody help me out?
Each of the following salts can be prepared from an acid and a base. Write the balanced molecular equation and net ionic equation for the preparation for each. Indicate states of the reactants and the...
Hi. In class, i am required to perform a titration where i am given a solution of sodium carbonate and a solution of hydrochloric acid of known concentration. I am to use the acid to calculate the percentage purity of the sodium carbonate.
Im not really sure how to go about doing this. The...
If I have a mixture of benzoic acid and benzil, and I add dichloromethane to it and extract it using sodium hydroxide, the benzoic acid reacts with the sodium hydroxide to form sodium benzoate, but what does the benzil react with. I know that its in the organic layer because it's neutral but...
Hello,
I did a lab on the recrystallization of benzoic acid. My solvent was hot water and used charcoal to adsorb any color impurities. I am trying to figure out how I should write a reaction and a mechanism for this. Is there even a reaction and mechanism I can write for this?
Any...
Homework Statement
Do not understand the question.
2. My Lab Results
Topic : Volumetric analysis - Acid base
purpose : To determine the exact concentration of a mineral acid, HXO4, and to determine the relative atomic mass of the element X.
Materials : KA1 is a mineral acid, HXO4...
Homework Statement
I'm just checking over the equation/reaction for butyraldehyde's solubility in H2SO4.
Homework Equations
See below.
The Attempt at a Solution
Will it be
CH3CH2CH2C(=O)H + H2SO4 --> HSO4- +
_________(+)
__________O-H
-----------||
CH3CH2CH2C-H
?
Thanks.
Hello everybody, I'm having difficulty understanding the rationalization behind the strengths of Bronstend Lowry acids and bases and my textbook isn't too helpful. Can someone please expalin to me: (1) What exactly is effective negative charge density? (2) how does electronegativiy correspond to...
Homework Statement
I just wanted to review what happens when methyl benzoate dissolves in sulfuric acid (the ionic species that arise). My workings/reasonings are below.
Homework Equations
See below.
The Attempt at a Solution
After the ester in placed in the acid, the...
Can somebody tell me the color the following items turn when purple Cabbage Indicator is added:
Water
Hydrogen peroxide
Isopropyl alcohol
Saline solution
Aspirin
Pepto-Bismol
Alka-Seltzer
Tonic water
Vinegar
and can you tell me if the items listed above are Acid or Base or Neutral...
A couple of questions:
1) How do I minimize it?
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3) Would a vegetarian diet cure acid reflux?
i'v synthesized benzoic acid from benzyl alcohol and i have a theoretical value for the yield and and experimental yield of impure acid.
Theoretical Yield = 5.93g
Impure Yield from experiment = 6.13g
Now, my paper asks for the percentage yield of my impure acid, how does that work?
If...
An experiment was carried out in class. Basically, Baking Soda was added to different concentrations of Ethanoic Acid. The plot of 'Maximum Foam observed' vs. 'concentration of the Acid'. The curve went up but then dropped noticeably! :confused:
So basically, with high concentrations or low...
I did an experiment in one of the labs and I have a question I need to figure out.
The experiment was the porduction of p-acetylaminotoluene, from p-toluidine.
My question is we used acetic acid and acetic anhydride, but which is the acetyalting species.
I thought of looking at the...
Hello people...could u help me pls...coz i am rly stuck in these thing like calculations...i know all right answers but i am not too sure how to get them...please if somebody of us has a few minutes could u help me with that?
Thank you very much.
1.,
When 0.25 g of sodium metal was added...
Chemistry questions
Q1: Calculate the amount of 6M HCl that would be required to neutralize and acidify (to ~pH2) the reaction mixture of 1g Benzaldehyde and 2mL 10M KOH.
I think this is the chemical equation:
Benzaldehyde + KOH + H+ -> Benzyl Alcohol + Benzoic Acid
Q2: 64% yield of 1,1...
[Chemistry Lab] Cannnizzaro Reaction
Hi! I am having some questions about my chemistry lab.
In the lab we are given 1 of the 5 unknown aldehyde (benzaldehyde, anisaldehyde, nitrobenzaldehyde, chlorobenzaldehyde, and dimethoxybenzaldehyde) and reacts it with methanol and KOH to undergo...
Sorry, I'm not much of a biology expert, but I was looking into the interactions between b5 and omega 3 fatty acids. I wanted some help clarifying this.
http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/pan_0196.shtml
Does that imply that it breaks down fatty acids and uses them as...