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Acid + Base Class # 1

Acid + Base Class # 1. OB: intro to Arrhenius theory, meet and greet tables K, L, and M. Acids and bases always starts with a good story. A long, long time ago, in a galaxy far, far away…. Please note, a great mustache!

gavin-mcleod
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Acid + Base Class # 1

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  1. Acid + Base Class # 1 OB: intro to Arrhenius theory, meet and greet tables K, L, and M

  2. Acids and bases always starts with a good story. A long, long time ago, in a galaxy far, far away…

  3. Please note, a great mustache! Svante ArrheniusFather of the Arrhenius Theory of Acids and BasesNobel Prize WinnerSwedish Chemist Extraordinaire The Arrhenius Theory of Acids and Bases covers nearly 99% of all acids and bases, and allowed chemists of all levels to finally grasp what acids and bases were, how they worked, and what happens when you put them together. There are other theories, for the 1% of solutions, including ammonia, which is important for us to also learn about as well. Arrhenius theory is nearly complete.

  4. The standard theory (Arrhenius) states that ACIDS are aqueous solutions containing an excess of hydrogen ions (exceed the hydroxide ion concentration). Arrhenius theory states that BASES are aqueous solutions containing an excess of hydroxide ions (exceeding the hydrogen ion concentration). ACIDSAcids we need to know are all listed in table K. In our class we will discuss all eight acids, hydrochloric, nitrous, nitric, sufurous, sulfuric, phosphoric, carbonic, and acetic (which is also known as ethanoic acid during organic chem).

  5. Let’s look at table K now. On it we’ll write near the top – STRONGEST and near the bottom – WEAKEST Acids are strong when there are lots of H+1 ions in solution, because the compounds dissociate well. When HCl is put into water, nearly all of the HCl becomes H+1 and Cl-1 ions The more hydrogen ions in solution, the stronger the acid. HCl dissociates very well. At the top of the list, the acids dissociate the easiest. Further down, especially acetic acid (vinegar) the acids do not dissociate well at all. Much of the compound dissolves into water as a polar molecule, only a few percent of the molecules actually ionize.

  6. Dissociation of acids… HCl(G) + H2O(L) HNO2(G) + H2O(L) HNO3(G) + H2O(L) H2SO4(G) + H2O(L) H3PO4(G) + H2O(L) H2CO3(G) + H2O(L) HC2H3O2(G) + H2O(L)

  7. Dissociation of acids… HCl(G) + H2O(L) H+1(AQ) + Cl-1(AQ) HNO2(G) + H2O(L) H+1(AQ) + NO2-1(AQ) HNO3(G) + H2O(L) H+1(AQ) + NO3-1(AQ) H2SO4(G) + H2O(L) H+1(AQ) + H+1(AQ) + SO4-2(AQ) H3PO4(G) + H2O(L) H+1(AQ) + H+1(AQ) + H+1(AQ) + PO4-3(AQ) H2CO3(G) + H2O(L) H+1(AQ) + H+1(AQ) + CO3-2(AQ) HC2H3O2(G) + H2O(L) H+1(AQ) + C2H3O2-1(AQ) NOTE… All acids start with an “H”, and all end with hydrogen ions in solution

  8. BASESBases we need to know are all listed in table L. In our class we will discuss all four bases, sodium hydroxide, potassium hydroxide, calcium hydroxide, and ammonia. Ammonia does not have hydroxides in its formula, but since it is a common and “normal” part of our regular lives, we will learn a separate theory to explain how it is a base. Bases have more hydroxide ions in solution than hydrogen ions.

  9. Let’s look at table L now. On it we’ll write near the top – STRONGEST and near the bottom – WEAKEST Bases are strong when there are lots of OH-1 ions in solution, because the compounds dissociate well. When NaOH is put into water, nearly all of the NaOH becomes Na+1 and OH-1 ions The more hydroxide ions in solution, the stronger the base. NaOH dissociates very well. At the top of the list, the bases dissociate the easiest. Further down, ammonia follows a different rule, which we will not cover today. It is a base, it acts like a base, but it’s different too. There are only 4 bases in our class, although all aqueous solutions containing hydroxides would be bases, like magnesium hydroxide or lithium hydroxide.

  10. Strong acids and strong bases have lots of ions in solution. Strong acids and strong bases make good electrolytes, they will conduct electricity well because of all the loose ions in solution. HCl(AQ) conducts better than carbonic or ethanoic acids. NaOH(AQ) conducts better than ammonia. All acids and all bases are electrolytes. Their relative conduction strengths are also top to bottom on tables K and L.

  11. Arrhenius theory states that aqueous solutions with excess hydrogen ions are acids, and that aqueous solutions with excess hydroxide ions are bases. It goes on to say… Acids plus bases will neutralize each other into water and a salt. Salts are ionic compounds (metal + nonmetal). Water is H20(L) Water can also be written as HOH(L)

  12. Combining acids and bases to react are sort of fancy double replacement reactions, but the reactants must be an acid and base, and will always create a salt and water. There will be no precipitates either. Let’s do the classic one first, then lots more… HCl(AQ) + NaOH(AQ) HCl(AQ) + NaOH(AQ) The hydrogen ion, and the hydroxide ion are both red. Those ions make the acid and the base. They get together to NEUTRALIZE each other.

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  14. Combining acids and bases to react are sort of fancy double replacement reactions, but the reactants must be an acid and base, and will always create a salt and water. There will be no precipitates either. Let’s do the classic one first, then lots more… HCl(AQ) + NaOH(AQ) HCl(AQ) + NaOH(AQ)HOH(L) + NaCl(AQ) The hydrogen ion and hydroxide ion make the water. The other ions make the salt, in this case the salt is sodium chloride.

  15. Write balanced chemical equations from these word equations of these acid base neutralization reactions… Nitric acid + potassium hydroxide Hydrochloric acid and calcium hydroxide Phosphoric acid plus lithium hydroxide Remember… start at the beginning, products are HOH + salt

  16. Write balanced chemical equations from these word equations of these acid base neutralization reactions… HNO3(AQ) + KOH(AQ) HCl(AQ) + Ca(OH)2(AQ) H3PO4(AQ) + LiOH(AQ)

  17. Write balanced chemical equations from these word equations of these acid base neutralization reactions… HNO3(AQ) + KOH(AQ) HOH(L) + KNO3(AQ) 2HCl(AQ) + Ca(OH)2(AQ) 2HOH(L) + CaCl2(AQ) H3PO4(AQ) + 3LiOH(AQ) 3HOH(L) + Li3PO4(AQ)

  18. Homework tonight… Print out and read the Acid Base Diary Go to arbuiso.com and look at the bottom of the home page and find the acid base link. Click it, look over what is there. Acid Base HW #1 will be collected tomorrow. Also due by Wednesday, the Solutions Lab + the Clock Lab. Buy a red Barron’s regents review book as soon as possible.

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