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Acid and Base. Ch 15 and 16 7-2. acids. 1. tastes sour. 2. conducts an electric current. 3. Causes certain dyes ( indicators) to change color. 4. Liberates hydrogen when it reacts with certain metals. 5. neutralizes basic solutions to form salts. Bases. 1. tastes bitter.
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Acid and Base Ch 15 and 16 7-2
acids • 1. tastes sour. • 2. conducts an electric current. • 3. Causes certain dyes ( indicators) to change color. • 4. Liberates hydrogen when it reacts with certain metals. • 5. neutralizes basic solutions to form salts.
Bases • 1. tastes bitter. • 2. conducts an electric current. • 3. causes certain dyes ( indicators) to change color. • 4. feels slippery. • 5. neutralizes acid solution to form salts.
Definition of Acids and Bases • An acid is a source of hydrogen ions (H+) or hydronium ions (H3O+ ) in solution. HCl(aq) + H2O(l) H3O+ (aq) + Cl- (aq)
A base is a source of hydroxide ions (OH-) e.g. NaOH(s) Na+ (aq) + OH- (aq) e.g. NH3 (aq) +H2O(l) NH4+ (aq) + OH-(aq)
H H – + O O Cl Cl H H H H B. Definitions • Arrhenius - In aqueous solution… • Acidsform hydronium ions (H3O+) HCl + H2O H3O+ + Cl– acid
H H – + N O O N H H H H H H H H B. Definitions • Arrhenius - In aqueous solution… • Bases form hydroxide ions (OH-) NH3 + H2O NH4+ + OH- base
conjugate acid conjugate base B. Definitions • Brønsted-Lowry • Acidsare proton (H+) donors. • Bases are proton (H+) acceptors. HCl + H2O H3O+ + Cl- acid base
Conjugate acid base pairs • conjugate base: the species that remains after an acid has given up a proton • conjugate acid: the species that is formed when a base gains a proton
conjugate acid conjugate base base acid NH3 + H2O NH4+ + OH-
In the two examples water first acts as a base, then as an acid. • Any species which can both accept and donate protons is called amphiprotic. (also known as amphoteric)
Give the conjugate acid for each of the following: Br – HSO4- CO32- HBr H2SO4 HCO3-
List the conjugate acids for the following Bronsted bases • OH - • CO32- • NO3- • HCO3- • CN - H2O HCO3- HNO3 HCO3 HCN
Give the conjugate base for each of the following: HF H3PO4 H3O+ F - H2PO4- H2O • Polyprotic - an acid with more than one H+
List the conjugate bases for the following Bronsted acids • H2SO4 • HPO42- • HCO3- • H3O+ • H2PO4- HSO4- PO43- CO32- H2O HPO42-
Review 2: Name the acid, base, conjugate acid and base for each reaction. CH3NH2 + H2O CH3NH3+ + OH - conjugate acid conjugate base base acid H3PO4 + H2O H3O + + H2PO4- conjugate acid conjugate base acid base HC2H3O2 + H2O H3O + + C2H3O2- acid base conjugate acid conjugate base CH3NH3+ + H2PO4-H3PO4 + CH3NH2 acid base conjugate acid conjugate base
Review 2: Name the acid, base, conjugate acid and base for each reaction. H2PO4- + OH-HPO42- + H2O conjugate base conjugate acid acid base HCN + H2O CN- + H3O + conjugate base conjugate acid acid base NH3 + H2O NH4+ + OH - base acid conjugate acid conjugate base NO2- + HCO3-CO32- + HNO2 base acid conjugate base conjugate acid