Chapter 14: Acids & Bases

Question 1

Define an Arrhenius acid. Give an example

Answer 1

Releases hydrogen ion when added to water.
Ex: HCl + h20 -> h30 + Cl

Question 2

Define an Arrhenius base. Give an example

Answer 2

Releases hydroxide ions when added to water.
Ex: NaOH + H20 -> Na + OH + H20

Question 3

Write chemical equations to show the neutralization reaction between an Arrhenius acid
and an Arrhenius base.

Answer 3

H2SO4 + 2KOH -> 2H2O + K2SO4

Question 4

Define a Bronsted-Lowry acid. Give an example

Answer 4

released proton when added to water. Ex: NH3 + H2O -><- NH4+
+ OH- BL base BL acid

Question 5

Define a Bronsted-Lowry base. Give an example that is NOT an Arrhenius base.

Answer 5

Absorbs a proton (H+) when added water. HOCl + H20 -><- ClO4- + HN4+

Question 6

Tell the reason a hydrogen ion is called a proton

Answer 6

When a hydrogen becomes an ion, it loses its electron. Because hydrogen only has 1 proton and electron pair. Hydrogen ion consists of one proton.

Question 7

Describe a hydronium ion

Answer 7

Hydronium is formed when a hydrogen ion forms with water

Question 8

Describe the concept of a conjugate acid-base pair within the Brønsted-Lowry theory of
acids and bases

Answer 8

Conjugate acids are paired with Bronsted Lowry bases. Whereas conjugate bases are pair with Bronsted Lowry acids. Both pairs are found on the opposite side of the equation. From Bronsted Lowry bases to conjugate acids, the molecules add a hydrogen ion. From Bronsted Lowry acid to conjugate base, the molecule loses hydrogen ion

Question 9

Given an acid chemical formula, write the conjugate base chemical formula. Include
formula charge

Answer 9

NH4+ + OH- -><- NH3 + H20
acid base C acid C base

Question 10

Given a base chemical formula, write the conjugate acid chemical formula. Include formula charge.

Answer 10

NH3 + H2O -><- NH4+ + OH-
base acid C acid C Base

Question 11

Explain the difference between a strong acid and a weak acid based on the equilibrium in a reversible chemical reaction between the acid and its conjugate base.

Answer 11

Strong acid releases 99% of H+ (releases all hydrogens). Weak acids release 5% or less of H+ (release very little)

Question 12

Give example of strong and weak acids

Answer 12

Strong acids: HCl, H2SO4
Weak acids: HC2H3O2, H3PO4

Question 13

Explain the self-ionization of water

Answer 13

A chemical reaction in which two water molecules make hydronium and hydroxide ion

Question 14

Remember that the pH scale measures the molar concentration of hydrogen (hydronium)
ions in solution.

Answer 14

pH scale measures the molar concentration of hydrogen ions in a solution

Question 15

Explain the meaning of representative pH values.

Answer 15

0.1MH+ = 1x10-1MH+ = pH1
0.01MH+ = 1x10-2MH+ = pH2
0.001MH+ = 1x10-3MH+ = pH3
0.0001MH+ = 1x10-4MH+ = pH4
0.00001MH+ = 1x10-5MH+ = pH5
0.000001MH+ = 1x10-6MH = pH6
0.0000001MH+ = 1x10-7MH = pH7 …..

Question 16

Tell relative acid or base strength based on pH value

Answer 16

Below pH7 = acidic [H+] > [OH-}
pH7 = neutral [H+] = [0H-]
Above pH7: basic/alkaline [H+] < [OH-]

Question 17

Explain pH indicators

Answer 17

compounds that change color in a solution that are used to determine the acidy or basicity of a substance

Question 18

Define a buffered solution

Answer 18

stabilizes the pH of a solution when a small amount of acid or base is added to it.

Question 19

Describe how the molecular components of a buffered solution respond to resist a change
in the solution pH when an acid is added to a buffered solution.

Answer 19

the buffer must remove the added H+ so the pH value doesn’t change

Question 20

Describe how the molecular components of a buffered solution respond to resist a change
in the solution pH when a base is added to a buffered solution.

Answer 20

the buffer must add H+ pH value is restored