ACIDS AND BASES 4/19/15. 1) Given the reactions:

Transcription

1 NAME: ACIDS AND BASES 4/19/15 ROW PD 1) Given the reactions: (A) NH3(g) + H2O(l) NH4 + + OH (B) HCl + H2O (l) H3O + + Cl As shown in equations (A) and (B) and based on the Bronsted theory, water is an amphoteric substance because it can 1) donate protons, only 2) accept protons, only 3) either donate or accept protons 4) neither donate nor accept protons 2) Which of the following ph values indicates the highest concentration of hydronium ions in a solution? 1) ph = 1 2) ph = 2 3) ph = 3 4) ph = 4 3) When the ph of a solution is changed from 4 to 3, the hydronium ion concentration of the solution 1) decreases by a factor of 100 2) increases by a factor of 10 3) decreases by a factor of 10 4) increases by a factor of 100 4) Which statement correctly describes a solution with a ph of 9? 1) It has a higher concentration of H3O + than OH and causes methyl orange to turn yellow. 2) It has a higher concentration of OH than H3O + and causes litmus to turn blue. 3) It has a higher concentration of H3O + than OH and causes litmus to turn blue. 4) It has a higher concentration of OH than H3O + and causes methyl orange to turn red. 5) Based on Reference Table F, which of these salts is the best electrolyte? 1) barium sulfate 2) magnesium carbonate 3) silver chloride 4) sodium nitrate 6) Given the balanced equation representing a reaction: NH3(g) + H2O( ) NH4 + + OH According to one acid-base theory, the NH3(g) molecules act as 1) a base because they accept H + ions 2) a base because they donate H + ions 3) an acid because they accept H + ions 4) an acid because they donate H + ions 7) Which substance is an electrolyte? 1) 2) 3) 4) 8) One alternate acid-base theory states that an acid is an 1) OH - acceptor 2) OH - donor 3) H + donor 4) H + acceptor 9) As an aqueous solution becomes more acidic, the hydroxide ion concentration 1) decreases 2) increases 3) remains the same 10) According to the Arrhenius theory, a base reacts with an acid to produce 1) ammonia and methane 2) ammonia and a salt 3) water and methane 4) water and a salt 11) Which compounds are classified as Arrhenius acids? 1) 2) 3) 4)

2 ACIDS AND BASES 12) The table below was compiled from experimental laboratory data. At what ph would all three indicators appear as yellow? 1) 8.7 2) 2.9 3) 1.9 4) ) Which substance is an Arrhenius base? 1) CH3OH 2) CH3Cl 1) accepts an OH ion 2) donates an OH ion 3) accepts an H + ion 4) donates an H + ion 3) LiOH 4) LiCl 14) According to one acid-base theory, a water molecule acts as an acid when the molecule 15) The results of testing a colorless solution with three indicators are shown in the table below. Which formula could represent the solution tested? 1) C6H12O6 2) C12H22O11 1) C6H12O6 2) KOH 3) NaOH 4) HCl 16) Which 0.1 M solution has a ph greater than 7? 1) hydrogen ions 2) hydroxide ions 3) KCl 4) CH3COOH 17) When dissolved in water, an Arrhenius base yields 3) oxide ions 4) hydronium ions 18) According to one acid-base theory, a base is an 1) Na + donor 2) H + donor 1) a salt 2) a hydrocarbon 3) an Arrhenius acid 4) an Arrhenius base 3) Na + acceptor 4) H + acceptor 19) When one compound dissolves in water, the only positive ion produced in the solution is H3O +. This compound is classified as 20) Given the reaction: NH3 + HCl NH4Cl In this reaction ammonia molecules (NH3) act as a base because they 1) accept hydrogen ions (H + ) 2) donate hydroxide ions (OH ) 3) donate hydrogen ions (H + ) 4) accept hydroxide ions (OH ) 21) Given the reaction at equilibrium: HSO4 + NH3 «SO4 2 + NH4 + What are the two species that are acids? 1) NH3 and NH4 + 2) NH3 and SO4 2 3) HSO4 and SO4 2 4) HSO4 and NH4 +

3 22) Which relationship is present in a solution that has a ph of 7? 1) [H + ] + [OH ] = 7 2) [H + ] < [OH ] 3) [H + ] = [OH ] 4) [H + ] > [OH ] 23) Which compound is an Arrhenius acid? 1) NH3 2) HCI 3) K2O 4) CaO 24) Which laboratory test result can be used to determine if KCl(s) is an electrolyte? 1) electrical conductivity of KCl 2) electrical conductivity of KCl(s) 3) ph of KCl(s) 4) ph of KCl ACIDS AND BASES 25) Given the balanced equation representing a reaction: According to one acid-base theory, the H2O( ) molecules act as 1) an acid because they donate H + ions 2) a base because they donate H + ions 3) an acid because they accept H + ions 4) a base because they accept H + ions 26) Given the reaction at equilibrium: S 2 + H2O «HS + OH Which species acts as base by accepting a proton in the forward reaction? 1) H2O 2) HS 3) S 2 4) OH 27) How are HNO3 and CH3COOH similar? 1) They are Arrhenius bases and they turn blue litmus red. 2) They are Arrhenius bases and they turn red litmus blue. 3) They are Arrhenius acids and they turn blue litmus red. 4) They are Arrhenius acids and they turn red litmus blue. 28) Which equation illustrates the amphiprotic properties of a reactant species? 1) NH2 + H2O( ) NH4 + + OH 2) HCl + H2O( ) H3O + + Cl 3) 2H2(g) + O2(g) 2H2O( ) 4) H2O( ) + H2O( ) H3O + + OH

4 ACIDS AND BASES Base your answers to questions 29 and 30 on the information below and on your knowledge of chemistry. In a titration, 50.0 milliliters of M HCl is neutralized by 38.5 milliliters of KOH. 29) Show a numerical setup for calculating the molarity of the KOH. 30) Complete the equation for the neutralization by writing the formula of the missing product. Base your answers to questions 31 and 32 on the information below. A 20.0-milliliter sample of HCl is completely neutralized by 32.0 milliliters of 0.50 M KOH. 31) According to the data, to what number of significant figures should the calculated molarity of the HCl be expressed? 32) Calculate the molarity of the HCl. Your response must include both a numerical setup and the calculated result.

5 Answer Key ACIDS AND BASES 1) 3 2) 1 3) 2 4) 2 5) 4 6) 1 7) 1 8) 3 9) 1 10) 4 11) 4 12) 4 13) 3 14) 4 15) 3 16) 2 17) 2 18) 4 19) 3 20) 1 21) 4 22) 3 23) 2 24) 1 25) 4 26) 3 27) 3 28) 4 29) (0.026 M)(50.0 ml) = MB (38.5 ml) 32) correct numerical setup. Acceptable responses include, but are not limited to: (MA)(20.0 ml) = (32.0 ml)(0.50 M) 0.80 M or for a response consistent with the student s numerical setup. Significant figures do not need to be shown. Note: Do not allow credit for a numerical setup and calculated result that are not related to the concept assessed by the question. 30) KCL ClK K + + CL K + + Cl 31) 2 or two.