Section 10.2 Worksheet PDF

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Brønsted-Lowry Definition of Acids and Bases Learning Objectives 

Recognize a compound as a Brønsted-Lowry acid or a Brønsted-Lowry base

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Illustrate the proton transfer process that defines a Brønsted-Lowry acid-base reaction.

Recognize a compound as a Brønsted-Lowry acid or a Brønsted-Lowry base 1. Give the definitions of a Brønsted-Lowry acid and a Brønsted-Lowry base. 2. Label each reactant as a Brønsted-Lowry acid or a Brønsted-Lowry base. HCl (aq) + NH3(aq) → NH4+(aq) + Cl- (aq) 3. Label each reactant as a Brønsted-Lowry acid or a Brønsted-Lowry base. H2O(l) + N2H4 (aq) → N2H5+ (aq) + OH- (aq) 4. Explain why a Brønsted-Lowry acid can be called a proton donor. 5. Explain why a Brønsted-Lowry base can be called a proton acceptor. Illustrate the proton transfer process that defines a Brønsted-Lowry acid-base reaction. 6. Write the chemical equation of the reaction of ammonia in water and label the Brønsted-Lowry acid and base. 7. Write the chemical equation of the reaction of methylamine (CH 3NH2) in water and label the Brønsted-Lowry acid and base. 8. Demonstrate that the dissolution of HNO3 in water is actually a BrønstedLowry acid-base reaction by describing it with a chemical equation and labeling the Brønsted-Lowry acid and base. 9. Identify the Brønsted-Lowry acid and base in the following chemical equation: C3H7NH2 (aq) + H3O+ (aq) → C3H7NH3+ (aq) + H2O (l)

10.Identify the Brønsted-Lowry acid and the Brønsted-Lowry base in each of the following equations: a. NO2- + H2O → HNO2 + OHb. HBr + H2O → H3O+ + Brc. HS- + H2O → H2S + OHd. H2PO4- + HCl → H3PO4 + Cl11.Write the chemical equation for the reaction that occurs when cocaine hydrochloride (C17H22ClNO4) dissolves in water and donates a proton to a water molecule. (When hydrochlorides dissolve in water, they separate into chloride ions and the appropriate cation.) 12.If codeine hydrobromide has the formula C 18H22BrNO3, what is the formula of the parent compound codeine? 13.Identify the conjugate acid-base pairs in this equilibrium NH2- + H2O

⇌

NH3 + OH-

14.Write the formula of the conjugate base of (a) HNO2 and (b) H2CO3. 15.Write the formula for the conjugate acid of (a) C6H5NH2 and (d) HCO3-. 16.Pyridinium chloride (C 5H5NHCl) dissolves in ethanol (C2H5OH) and separates into pyridium ions (C5H5NH+) and chloride ions. The pyridinium ion can transfer a hydrogen ion to a solvent molecule. Write a balanced chemical equation for this process and identify the Br ønsted-Lowry acid and base. 17.Caffeine (C8H10N4O2) is a stimulant found in coffees and teas. When dissolved in water, it can accept a proton from a water molecule. Write the chemical equation for this process and identify the Br ønsted-Lowry acid and base.

ANSWER KEY 1. A Brønsted-Lowry acid is a proton donor, while a Brønsted-Lowry base is a proton acceptor. 2. HCl: Brønsted-Lowry acid; NH3: Brønsted-Lowry base 3. H2O: Brønsted-Lowry acid; N2H4: Brønsted-Lowry base 4. A Brønsted-Lowry acid gives away an H+ ion—nominally, a proton—in an acidbase reaction. 5. A Brønsted-Lowry base accepts an H+ ion (a proton) in an acid-base reaction. 6. NH3 + H2O → NH4+ + OH- (here NH3 = Brønsted-Lowry base; H2O = BrønstedLowry acid) 7. CH3NH2 + H2O → CH3NH3+ + OH- (here CH3NH2 = Brønsted-Lowry base; H2O = Brønsted-Lowry acid 8. HNO3 + H2O → H3O+ + NO3- (here HNO3 = Brønsted-Lowry acid; H2O = BrønstedLowry base) 9. C3H7NH2 (aq) + H3O+(aq) → C3H7NH3+ (aq) + H2O(l) (here H3O+ = BronstedLowry acid; C3H7NH2 = Bronsted-Lowry base) 10.a. NO2- (base) + H2O (acid) b. HBr (acid) + H2O (base) c. HS- (base) + H2O (acid) d. H2PO4- (acid) + OH- (base) e. H2PO4- (base) + HCl (acid) 11. Cocaine hydrochloride dissolves in water : C 17H22ClNO4. → Cl- + C17H22NO4+ Cation donates a proton to a water molecule: C17H22NO4+ + H2O → H3O+ + C17H21ClNO4 12.C18H21NO3 13.H2O (acid) and OH- (base); NH2- (base) and NH3 (acid) 14.a. NO2- is the conjugate base of HNO2 b. HCO3- is the conjugate base of H2CO3 15.a. C6H5NH3+ is the conjugate acid of C6H5NH2 b. H2CO3 is the conjugate acid of HCO 316.C5H5NH+ (solv) + C2H5OH (l) → C5H5N (solv) + C2H5OH2+ (solv) B-L acid B-L base 17.C8H10N4O2 (aq) + H2O (l) → C8H11N4O2+ (aq) + OH- (aq) B-L base B-L acid...