Acid Base and Salt Question and Answers
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Answers:1-Acid: If it has hydrogen in it. Base: If it has OH in it Salt: If it was the result of a neutralization reaction between a acid and base. You get the salt and water. 2-Well that has many rules...but, all soluble ionic substances are strong. HCl,HI, HBR, H2SO4, NHO3 are all strong. OH with any group 1 elements or Ca,Sr, Ba are strong bases. 3-An example: MnS(s)+HCl(aq)---->MnCl2(aq)+H2S(g) First: Balance equation MnS(s)+2HCl(aq)---->MnCl2(aq)+H2S(g) Second: Dissociate all the strong, soluble compounds. The compounds that are not strong and soluble, just lave them alone. MnS(s)+2H+(aq)+2Cl-(aq)---->Mn+2(aq)+2Cl-(aq)+H2S(g) Third: Omit spectator ions (ions that had no change at all) MnS(s)+2H+(aq)---->Mn+2(aq)+H2S(g)
Answers:Are you sure you got the number right for gastric juice? If your teacher really wrote 7.25 on the quiz, then the answer is slightly basic, because anything with a pH greater than 7 is basic. Since 7.25 is just a little bit greater than 7, I would call this slightly basic. However, in reality gastric juice is very acidic with a pH around 2, and it is referred to as both gastric juice and gastric acid. As for why it is basic or acidic, this is based on the definition of these terms. Any solution with a pH greater than 7 is by definition basic, and any solution with a pH less than 7 is by definition acidic. So if your teacher gives you the pH, you just need to determine if it is greater or less than 7, and do not need to know anything else about the solution. Phosphoric acid, H3PO4, has three acidic OH groups, and each one is capable of losing a hydrogen. If you're just talking about dihydrogen phoshpate, then hydrogen is the cation and dihydrogen phoshpate is the anion. A buffer system allows you to maintain the solution at a roughly constant pH even while adding acidic or basic molecules to solution. If you add a few drops of hydrochloric acid to a beaker of pure water, or to a beaker containing an non-buffered aqueous solution, there will be a dramatic change in pH and the solution will become more acidic (how much it changes depends on the exact amount of water and hydrochloric acid you are using). However, if you have a buffer that can act as a base at pH of your solution, it will bind to the hydrogen ions released by hydrochloric acid, there will be no increase in the concentration of "free hydrogen ions" (which are actually hydronium ions, H3O+). If you add too much of an acid or a base, you will overwhelm the buffer and eventually you will be able to change the pH of the solution. Each buffer works over a specific range of pH values. Phosphoric acid/phosphates are excellent buffers because of the three acidic groups. Each hydrogen can bond to or dissociate from its oxygen over a specific range of pH values, but the range is different for each of the three acidic groups. Buffer systems with only one acidic group are effective over a much narrower pH range. To determine which buffer system is appropriate for a given experiment, you need to know the Ka (acid dissociation constant) or pKa for each acidic group in the molecule. Phosphoric acid has three Ka's, one for each of its three acidic groups. When determining which is the cation and which is the anion, it does not make a difference whether or not you are using Arrhenius acid-base theory or Br nsted-Lowry acid-base theory, except some Br nsted-Lowry reactions do not involve ionic reactants or products. The Wikipedia aritcle on acids has a brief description of the three major acid-base theories, and while it does not answer your question directly, the section on Br nsted-Lowry theory gives an example of reactions that do not involve ions, and the entire section discusses how all of the different definitions of an acid (or a base) relate to each other: http://en.wikipedia.org/wiki/Acid#Technical_definitions .
Answers:13) when the compounds dissolve (or break apart) in water, you will get ions (in a) K+, b) H+, c) K+) but in d, there are none. C2H5OH wont really break down into any metals. Metals are good conductors of electricity (and so are acids, hence the H+) 25) i assume you know the factor (3 to 4 = 10, 3 to 5 = 100, 3 to 6 = 1000....just keep adding 0's or multiply by 10). Hydronium is H+ and hydroxide is OH- (oxide = oxygen) If the pH goes from 3 to 6, it's becoming less acidic, 1 is most acidic and 14 is least acidic (better known as most basic). If it's becoming less acidic (AKA more basic), then there is a decrease of H+ (AKA increase in OH-), or in more chem terms a decrease in hydronium ions and an increase in hydroxide ions hope it helped
Answers:2) In a neutralization reaction, the produced salt's cation is always from the base and the anion of the salt is always from the acid. ex. NH4Cl: NH4+ is from the weak base ammonia and the Cl- is from the strong acid Hydrchloric acid. 3) Any time you have a 1) weak acid and a 2) salt that contains the anion of the weak acid (conjugate base), by definition you'll have a buffer. ex. acetic acid (weak acid) and sodium acetate (acetate ion-conjugate base). Also if you have a ) weak base and a 2) salt that contains the cation of the weak base (conjugate acid), by definition you'll have a buffer. ex. ammonia (weak base) and ammonium chloride (ammonium ion-conjugate acid)