# Chem 32 ch.7

 What are acids? Substances that can donate an H+ atom to some other molecule are called acids. If you put HCl into water ( H2O ) the HCl will give its H to H2O to create Cl- and H3O+, so, HCl is an acid. Acids are sometimes called "proton donors". What are bases? Compounds tha form hydroxide ions when they dissolve in water are bases. When an ionic compound like NaOH dissolves in water it breaks up into Na+ and OH-, the OH- is a hydroxide ion, so NaOH is a base. What is hydronium? H3O. What is the ion product of water? The ion product ( product as in multiplication ) of water is the relationship of H3O+ and HO- in any aqueous ( water based ) solution. The molarity of H3O+ in the solution times the molarity of HO- in the solution will equal 1 x 10-14. molarity of H3O+ x molarity of OH- = 1x10-14 ( square brackets around a compound mean that the formula is talking about the molarity of the compound in the brackets... ) [H3O+] x [HO-] = 1 x 10-14 In the aqueous solution of tummy acid the molarity of H3O+ is .02 ( .02M H3O+ ). Using the ion product of water, what is the molarity of HO- ions in tummy acid? [H3O+] x [HO-] = 1x10-14 .02 x ??? = 1x10-14 1x10-14 / .02 = 5x10-13M What is pH? pH is a measurement of how much H3O+ is in an aqueous solution. It starts with a measurement of moles per liter ( molarity, M ) of H3O+ in an aqueous solution. If the molarity of H3O+ in a solution is 10-3M then the pH of the solution is simply 3. If the molarity of H3O+ in a solution is 10-9 then the pH of the solution is 9. [H3O+] x [OH-] = 10-14 So when pH is 7 there are equal amounts of H3O+ and OH-. A high pH, like pH 10, would mean the M of H3O+ in the solution is 10-10, which is a smaller number than say 10-4. So, a low ( lower than 7 ) pH has more H3O+ in it than HO-. So a low pH, means more H3O+ than HO-, means acidic. High ph ( higher than 7 ) means less H3O+, more OH-, means more basic, less acidic. More H3O+ ( than HO- ) means... More acidic. Lower than 7 ph. More OH- ( than H3O ) means... More basic. Higher than 7 ph. What is something that all aqueous solutions have in common? All aqueous solutions have some water in them ( it's what makes them aqueous! ) and since there is some amount of self ionization in water, all aqueous have some amount of H3O+ pH of less than 7 is... Acidic. A pH of 7 is... neutral. pH of more than 7 is... basic. or, alkaline. What is an ionization reaction? A chemical reaction that results in ions as products. What do all -common- acids have in common with each other? All common acids are made up of molecular compounds, made up of non-metalic atoms held together with covalent bonds. All acids are electrolytes. All acids form ions when they dissolve in water, therefore all acids are electrolytes. Strong electrolyte... Also called a "strong acid". An acid is a strong electrolyte when many of its molecules donate an H+ to other molecules. The more easily a compound's molecules ionize ( break up into ions ) in a solution, the more ions it produces as products and the better it conducts electricity. All strong acids ionize completely. Weak electrolyte... Also called a "weak acid". An acid is a weak electrolyte when the molecules that make it up do not give very many H+ protons to other molecules in a solution. In this case, not as many molecules ionize ( break up into ions ) as a product and the solution does not conduct electricity well. Weak acids ionize in range ability to ionize. Some weak acids ionize more than other weak acids. What is "strength of acid"? An acid's ability to donate a proton. A strong acid has a high "strength of acid" and donates H+ atoms more easily. Weak acids have a low "strength of acid" and do not donate H+ protons so easily. Remember:strong acid = low pH = more acidic weak acid = high pH = less acidic What is a hydroxyl group? A hydroxyl group is a H atom covalently bonded to an O atom, it is a polar bond with H being positive and O being negative, like in water. How to identify a molecule as acidic... It must have at least one hydroxyl group, one H covalently bonded to an O. The atom that this O is bonded to will usually have another O bonded to it. H---O---X---O HOXO! Identifying acid as strong or weak by molarity... Strong acids ionize completely. So if you put .1 moles of a strong acid into water the acid/water solution will have .1mols of H3O+ because every one of the acid molecules will have given a H+ to a water molecule. What is a base? Any substance that can remove a hydrogen proton from a water molecule is a base. Or Any compound that can bond to H+. Bases always produce hydroxide ions when they dissolve in water. This causes the amount of OH- ( hydroxide ions ) in the solution to increase. More OH- means more basic, means higher pH. How to identify bases? Most anions ( negatively charged ions ) are bases. Phosphate for example, PO43- is an anion, a negatively charged ion. It is a base. Also, most molecules that have a nitrogen covalently bonded to a carbon, hydrogen, or both are bases. How to identify bases as strong or weak... In a strong base, every molecule of the base will pull a H+ from a water molecule when added to water. More H3O+ than OH- equals... acidic More OH- than H3O+ means... basic. Bases always produce hydroxide ions when dissolved in water. Bases always produce hydroxide ions when dissolved in water. When a base is added to water... it takes a H proton from a water molecule and leaves OH-, hydroxide, behind. More hydroxide in the solution raises the solution's pH. Bases always have a pH above 7. Hydroxide ( OH- ) itself is a strong base. Hydroxide ( OH- ) itself is a strong base. Sulfide ( S2- ) is a strong base. Sulfide ( S2- ) is a strong base. What is a conjugate pair? When a reactant acid loses an H, it ends up as a product minus one H ( HSO4 becomes SO4, itself a base ). The two together are a conjugate pair. The reactant is the acid, the product is the conjugate base. HSO4 + H2O <---> SO42- + H3O+orWhen a reactant base without an H ends up as a product that has gained an H ( HPO42-, a base becomes H2PO4-, itself an acid ) the two are a conjugate pair. The reactant is the base, the product the conjugate acid. HPO42- + H2O <---> H2PO4- + OH- What is an acid-base reaction? When an acid and a base are mixed together a proton ( H+ ) moves from the acid to the base. All acid-base reactions are proton transfers. :) When a hydrogen atom / proton / H+ moves from an acid to a base, it leaves the binding electrons behind. When a hydrogen atom / proton / H+ moves from an acid to a base, it leaves the binding electrons behind. What does "amphiprotic" mean? The term amphiprotic refers to a compound that can act as an acid or a base, being able to either lose an H+ or gain an H+. How to identify amphiprotic substances? Negative ions ( anions ) that have an ionizable H+ ( an H+ proton that can come off to form an acid ) are usually amphiprotic substances. What is the normal pH range of blood plasma? 7.35 - 7.45 Plasma pH below 6.8 causes death within seconds. What is a buffer ( where pH is concerned )? A buffer is a solution ( two or more compounds combined ) that resists a change in pH when an acid or base is added to it. A buffer must contain a substance that can neutralize acids and a substance that can neutralize bases. Most buffers are solutions that contain a conjugate acid-base pair. AuthorGhoelix ID106051 Card SetChem 32 ch.7 Descriptionchem 32 chapter 7 Updated2011-10-09T09:46:26Z Show Answers