1. Unit 10- Acids and Bases Acidity Alkalinity Arrhenius acid Arrhenius base Bronsted-Lowry acid Bronsted-Lowry base Buffer Electrolyte Hydrogen ion Hydronium ion Indicator Neutralization pH scale Salt Titration

2. Properties of Acids Have sour taste – ***take my word, don’t taste lab chemicals Can conduct electric current in solution – Electrolytes – Good conductor= strong acid – Poor conductor= weak acid Turns blue litmus paper red “blue to red a-cid” Most common acids are liquid or gas React with metals to produce H 2 gas – Above H 2 in Table J will react (single-replacement) React with bases to form salt and water – Neutralization (double- replacement Can generate hydronium ions H 3 O + in water pH less than 7

3. Acids Sulfuric- car batteries Ascorbic- tomatoes

4. Properties of Bases Have bitter taste – ***take my word, don’t taste lab chemicals Can conduct electric current in solution – Electrolytes – Good conductor= strong base – Poor conductor= weak base Most common bases are solid React with acids to form salt and water – Neutralization (double- replacement Can generate hydroxide ions OH - in water Turns red litmus paper blue “blue base” pH greater than 7

5. Bases Sodium bicarbonate

6. Acid and Base Strength Due to degree of ionization Complete dissociation-strong acid or base

7. Definitions of Acids and Bases Arrhenius Theory- – Arrhenius acid- produces H + or H 3 O + as the only positive ions in solution Hydrogen ions will attract to water molecule and form hydronium ions – Arrhenius base- produces OH - ions in solution Except!!! Not all bases have OH - ions Drawbacks: – Limited to aqueous solutions – Can’t classify amphoteric substances (substances that act as bases and acids)

8. Arrhenius acid is a substance that produces H + (H 3 O + ) in water Arrhenius base is a substance that produces OH - in water

9. Definitions of Acids and Bases con’t Br Ø nsted-LowryTheory- – B-L acid- proton donor – B-L base- proton acceptor – Proton = hydrogen ion that has lost its electron A Brønsted-Lowry acid is a proton donor A Brønsted-Lowry base is a proton acceptor acid conjugate base base conjugate acid

10. Definitions of Acids and Bases con’t All Arrhenius acids are also B-L acids B-L bases expand the substances that can be considered bases

11. Naming acids If an acid molecule forms 1 H ion it’s a: – Monoprotic acid (HCl) If an acid molecule forms 2 H ions it’s a: – Diprotic acid (H 2 SO 4 ) If an acid molecule forms 3 H ions it’s a: – Triprotic acid (H 3 PO 4 )

12. Naming acids con’t For binary acids: – Hydro + element name – ine + ic + acid – Ex: HCl- hydrochloric acid – Try HF- _________________________ For ternary acids: containing H, O and another element – 3 rd element name, modify to end in –ic or –ous + acid – Ex: HNO 3 - nitric acid nitrogen –ogen + ic + acid – Try HNO 2 - _____________________

13. Naming bases Name of positive ion + hydroxide – Ex: Ba(OH) 2 - barium hydroxide – Try KOH- ____________________ No oxygen  More oxygen  Less oxygen 

14. Reactions with acids and bases Acids and metals- – Use Table J in Ref Tables – Acid will react with anything above H 2 – Single replacement rx’s Zn(s) + 2HCl(aq)  H 2 (g) + ZnCl 2 (aq) Neutralization reactions- – Arrhenius acid + Arrhenius base  salt + water – Equivalence pt- pt at which neutralization is complete; when H 3 0 + ion = OH - ions

15. Neutralization Rx Words: Hydrochloric acid + sodium hydroxide  water + sodium chloride Chemical formulas: HCl(aq) + NaOH(aq)  H 2 O(l) + NaCl(aq) Ions: H + (aq) + Cl - (aq) + Na + (aq) + OH - (aq)  H 2 O(l) + Na + (aq) + Cl - (aq) Omitting spectator ions: H + (aq) + OH - (aq)  H 2 O(l) or H 3 O + (aq)+ OH - (aq)  2H 2 O(l)

16. Neutralization Rx’s con’t Diprotic acid + dihydroxy base makes 2 water molecules – Ex: Ca(OH) 2 + H 2 SO 4  2H 2 O + CaSO 4 Acids and bases with unequal H+ and OH- needs to be balanced – Ex: ___Mg(OH) 2 + __HCl  __H 2 O + ___MgCl 2 (two) (one) Salts produced- ionic substance with a metal and nonmetal or polyatomic ion

17. Titrations Process of adding a measured volume of an acid or base of known concentration to an acid or base of unknown concentration until neutralization occurs C acid x V acid = C base x V base (known) (known) = (unknown) (known) molarity x volume = molarity x volume Standard solution= soln of known concentration There needs to be a 1:1 ratio of H + to OH - – Diprotic ex: 2.5M H 2 SO 4 = 5M H + – Triprotic ex: 2MH 3 PO 4 = 6M H + – Dihydroxy base ex:.5MBa(OH) 2 = 1M OH -

19. Acidity and Alkalinity of Solutions Relative strength of an acid or base in terms of their H+ or OH- concentrations H 2 O  H+ + OH- – Le Chateliers principle [H + ] = [OH - ] – If one increases the other decreases If you add HCl to water H + increases so it becomes more acidic

20. pH scale Expresses the strength of acids and bases Instead of using very small numbers, we just use the NEGATIVE power of 10 on the Molarity of the H + (or OH - ) ion. pH change of 1 is a 10 fold increase or decrease in ions

22. pH indicators Substance that changes its color when it gains or loses a proton (H+ ion) Universal indicators are a mix of a few indicators pH meter- electric instrument with probes sensitive to H 3 O + creates voltage between probes

23. Buffers Solutions that resist change in pH Weak acid or base Usually a weak acid and its conjugate base Stabilizes pH – Foods, shampoo, antacids, blood