Chapter 19: Acids, Bases & Salts
Calculate the pH or H+ for each solution. b. pH= 13.20
-log[H+] 10x (-13.20) 6.3 x 10^-14
Identify the products and write balanced equations for each neutralization reaction. b. HCl + Ca(OH)2 -->
2HCl + Ca(OH)2 --> CaCl2 + 2H2O products: H2O and CaCl2
Write a balanced equation for the reaction of each metal with water: lithium
2Li(s) + 2H2O --> 2LiOH(s) + H2(g)
Calculate the pH for the following solutions and indicate whether each solution is acidic or basic. b. [OH-] = 1 x 10^-2 M
= - log 1 x 10^-2 = 2 pH =2 ; acidic
What is a lewis acid and a lewis base? In what sense is the lewis theory more general than the Arrhenius and Bronsted Lowry theories?
A lewis base donates a pair of electrons while a lewis acid accepts a pair of electrons. It is more general because it includes molecules that are not classified as Bronsted Lowry acids or bases
Write a general word equation for a neutralization equation.
Acid + Base --> Salt + Water
How did Arrhenius define an acid and a base?
Acids are compounds that contain hydrogen and when placed in aqueous solution, ionize to form hydrogen. Bases are compounds that ionize to yield hydroxide ions in aqueous solutions.
Explain why solutions of salts that hydrolyze in water do not have a pH of 7.
Anions form salt that is produced by neutralization of weak acid and strong bases. This will remove protons from water forming OH- ions.
Classify each compound for the dissociation of each compound in water: H2SO4
Arrhenius Acid
Classify each compound for the dissociation of each compound in water: HBr
Arrhenius Acid
Classify each compound for the dissociation of each compound in water: C2H5COOH
Arrhenius acid
Classify each compound for the dissociation of each compound in water: HNO3
Arrhenius acid
Classify each compound for the dissociation of each compound in water: KOH
Arrhenius base
Write a balanced equation for the reaction of each metal with water: barium
Ba(s) + 2H2O(l) --> Ba(OH)2(g) + H2(g)
What is the concentration of H+ and OH- in pure water at 25 degrees C?
Both H+ and OH- have concentrations of 10^-7
Identify each reactant in the following equations as a hydrogen-ion donor (acid) or a hydrogen ion acceptor (base). - H2O + CH2COO -> <- CH2COOH + OH-
CH3COO- : acceptor ; H2O : donor
Identify each reactant in the following equations as a hydrogen-ion donor (acid) or a hydrogen ion acceptor (base). - CH3COOH + H2O -> <- H3O + CH3COO-
CH3COOH : donor ; H2O : acceptor
Write an equation showing the ionization of water.
H2O --> H+ + OH-
Identify the products and write balanced equations for each neutralization reaction. c. H2SO4 +NaOH -->
H2SO4 + 2NaOH --> Na2So4 + 2H2O products: Na2SO4 and H2O
What is the molarity of a sodium hydroxide if 20 mL of the solution is neutralized by each of the following 1.00 M solutions? b. 17.4 mL of H3PO4
H3PO4 + 3NaOH --> Na3PO4 + 3H2O 0.0174 L H3PO4 x 1 mol H3PO4 / 1 L H3PO4 x 3 mol NaOh / 1 mol H3PO4 = 0.0522 mol NaOH M= 0.0522 mol NaOH / 0.020 L = 2.61 M
Write an equation showing why an aqueous solution of sodium hydrogen carbonate is basic.
HCO3- + H2O --> H2CO3 + OH-
Identify the products and write balanced equations for each neutralization reaction. a. HNO3 + KOH -->
HNO3 + KOH --> KNO3 + H2O products: H2O and KNO3
Identify each reactant in the following equations as a hydrogen-ion donor (acid) or a hydrogen ion acceptor (base). - HNO3 + H2O→H3O+ +NO3−
HNO3 - hydrogen ion donor ; H2O - hydrogen ion acceptor
Write each equation for the dissociation of each compound in water: potassium hydroxide
KOH(s)→K+(aq)+OH−(aq)
Write the expression for Ka for each acid. Assume only one hydrogen is ionized. a. HF
Ka= [H-] [F-] / HF
Would a strong acid have a large or small Ka?
Large because the larger the Ka, the stronger the acid. Ka measures how much an acid dissociates. A strong acid would have a larger Ka.
Write each equation for the dissociation of each compound in water: magnesium hydroxide
Mg(OH)2(s)→Mg+(aq)+2OH−(aq)
Identify each reactant in the following equations as a hydrogen-ion donor (acid) or a hydrogen ion acceptor (base). - NH3 + H2O -> <- NH4+ + OH-
NH3 : acceptor H2O: donor
What is the molarity of a sodium hydroxide if 20 mL of the solution is neutralized by each of the following 1.00 M solutions? a. 28 mL of HCl
NaOH + HCl --> NaCl + H2O 0.028 mol / 0.02 L = 1.4 M
Calculate the pH for the following solutions and indicate whether each solution is acidic or basic. c. [OH-] 1 x 10^-8M
POH= - log [OH-] -log [1.0 x 10^-8] pH + pOH = 14 pH= 6 ; acidic
What kinds of salts hydrolyze in water?
Salts with a cation from a weak base and an anion from a strong acid or a cation strong base and weak acid.
What are the hydroxide ions concentration for the solutions with the following pH values: a. 4.00
[H+][OH-] = 1 x 10^-14 | [1 x 10^-4] [1 x 10^-10] = 1 x 10^-14 | answer = 1 x 10^-10
Why are Mg(OH)2 and Ca(OH)2 considered to be strong bases even though their saturated solutions are only mildly basic?
They are slightly soluable in water because of their divalent positive charges. Their Kb values are large and they dissociate hydroxide ions completely so they are considered to be strong bases.
A buffered solution cannot absorb an unlimited amount of acid or base.
This is true because a buffered solution will reach a point in which the buffer capacity has reacted in which the solution cannot absorb anymore H+ or OH- ions in the buffered solutions.
Label the conjugate acid base pairs in each equation. b. CH3COOH + H2O -> <- H3O + CH3COO-
[CH3COOH and CH3COO-] and [H2O and H3O+]
Label the conjugate acid base pairs in each equation. d. CH3COOH + H2O -> <- H3O + CH3COO-
[CH3COOH and CH3COO-] and [H2O and OH-]
Calculate the pH or H+ for each solution. a. [H+] = 2.4 x 10^-6
[H+] = 2.4 x 10-6M pH= -log [H+] pH= -log[2.4 x 10^-6] pH = 5.62 acidic
Write the expression for Ka for each acid. Assume only one hydrogen is ionized. b. H2CO3
[H+] [HCO3-] / H2CO3
What are the hydroxide ions concentration for the solutions with the following pH values: c. 12.00
[H+][OH-] = 1 x 10^-14 | [1 x 10^-12] [1 x 10^-2] = 1x10^-14 answer = 1 x 10^-2
What are the hydroxide ions concentration for the solutions with the following pH values: b. 8.00
[H+][OH-] = 1 x 10^-14 | [1 x 10^-8] [ 1 x 10^-6] = 1x10^-14 answer = 1 x 10^-6
Calculate the pH for the following solutions and indicate whether each solution is acidic or basic. a. [H+] = 1 x 10^-2M
[H+]= [Kw]/[OH−] = 10^-14/10^-2 = 1 x 10^-12M pH = -log [H+] = - log 1 x 10^-12 = 12 basic
Label the conjugate acid base pairs in each equation. a. HNO3 + H2O→H3O+ +NO3−
[HNO3 and NO3-] and [H2O and H3O+]
Label the conjugate acid base pairs in each equation. c. NH3 + H2O -> <- NH4+ + OH-
[NH4+ and NH3] and [H2O and OH-]
Predict whether an aqueous solution of each salt will be acidic, basic , or neutral. b. NH4NO3
acidic
Predict whether an aqueous solution of each salt will be acidic, basic , or neutral. f. NH4Cl
acidic
Classify each compound for the dissociation of each compound in water: Ca(OH)2
arrhenius base
Why is the pH of pure water at 25 degrees C equal to 7.00?
at 25 degrees C, the hydrogen ion concentration in pure water is 1 x 10^-7. The pH is 7.
Predict whether an aqueous solution of each salt will be acidic, basic , or neutral. a. NAHCO3
basic
Predict whether an aqueous solution of each salt will be acidic, basic , or neutral. d. NA2Co3
basic
How is the pH of a solution calculated?
by taking the -log of the H+ concentration.
What is the characteristic of the end point of a titration?
change in color of indicator
Predict whether an aqueous solution of each salt will be acidic, basic , or neutral. c. KCl
neutral
Predict whether an aqueous solution of each salt will be acidic, basic , or neutral. e. Na2SO4
neutral
Identify each compound as a strong or weak acid or base. b. HCl
strong acid
Identify each compound as a strong or weak acid or base. d. H2SO4
strong acid
Identify each compound as a strong or weak acid or base. a. NaOH
strong base
Identify each compound as a strong or weak acid or base. c. NH3
weak base