Compare and Contrast Characteristics of Acids and Bases

Unit 12

Acids and Bases Notes

Compare and Contrast characteristics of Acids and Bases

Acid / Base
Tastes / sour / bitter
Turns litmus paper / red / blue
Conducts electricity / Yes / Yes
Neutralizes / Bases / Acids
Reacts with / Reacts with metal to form H2

Categories of Acids and Bases (may fall under one or more categories)

Lewis
Bronsted-Lowry
Arrhenius

Acid Definitions and Examples

Lewis Acid / is an atom or molecule that accepts an electron pair /
Bronsted-Lowry acid / is compound that breaks down to produce a H+ in solution
Conjugate base is particle that remains when acid has donated its H+ /
Arrhenius acid / is a molecule that when dissolved in water will donate a H+ in solution. This is also known as a proton donor. /

How to name acids

Original Suffix / Change suffix to / Example
-ide / Hydro______ic acid / HF
Hydrofluoric acid
-ate / -ic acid / H2SO4
Sulfuric acid
-ite / -ous acid / H2SO3
Sulfurous acid

Example 1

Name / Formula
Acetic Acid / HC2H3O2
Carbonic Acid / H2CO3
Hydrochloric acid / HCl

Classifying Acids

Strong Acids disassociate COMPLETELY in solution

Examples: Hydroiodic acid (HI), Hydrobromic acid (HBr), Perchloric acid (HClO4), Hydrochloric acid (HCl), Sulfuric acid (H2SO4), and Nitric acid (HNO3)

Weak Acids disassociate PARTIALLY in solution

Example 2

Demonstrate an example of a Lewis Acid using HCl

Example 3

Demonstrate an example of a Brownsted Lowry Acid using H2SO4

Example 4

Demonstrate an example of an Arrhenius acid using HF

Base Definitions and Examples

Lewis Base / is an atom or molecule that donates an electron pair /
Bronsted-Lowry base / is any atom or ion capable of accepting or bonding to a free proton in solution
Conjugate acid is the particle that remains when base gains H+ /
Arrhenius base / is a molecule that when dissolved in water will break down to yield OH- in solution /

How to name a base

There are no special naming requirements for bases

Example 5

Name / Formula
Ammonia / NH3
Calcium Hydroxide / Ca(OH)2
Lithium Hydroxide / LiOH

Classifying Bases

Strong Bases disassociate COMPLETELY in solution

Examples: all group 1 hydroxides, calcium hydroxide (Ca(OH)2), barium hydroxide (Ba(OH)2), and strontium hydroxide (Sr(OH)2)

Weak Bases disassociate PARTIALLY in solution

Example 6

Demonstrate an example of a Brownsted-Lowry Base using LiOH

pH scale is the measure of an acid or bases H+ concentration and tells the strength of the acid or base

The strongest acid is found at a pH of 0

The strongest base is found at a pH of 14

pH is a logarithmic scale

pH + pOH = 14

How to calculate pH using H+ concentration

pH= -log [H+]

[H+] indicates the concentration of hydrogen ions in solution. Concentration (as before in solutions unit) is measured in molarity.

How to calculate pH using OH- concentration

pOH= -log [OH-]

[OH-] indicates the concentration of hydroxide ions in solution. Concentration (as before in solutions unit) is measured in molarity.

Substitute the pOH value into the following equation and solve for pH

pH + pOH = 14

How to calculate H+ concentration from pH

[H+] = -10pH

This is the 2nd button then log in the calculator. Use the same process for the OH- concentration using the pOH.

Example 7

A 0.4 M solution of HCl has a pH of______. Is this an acid or a base?

Example 8

An H2SO4 solution has a pH of 0.25. What is the concentration of H2SO4 on the label of the bottle?

Bronsted-Lowry Acid Base Practice

In the exercise, Bronsted-Lowry Acids and Bases, it was shown that after on acid has given up its proton, it is capable of getting back that proton and acting as a base, conjugate base is whatis left after an acid gives up a proton. The stronger the acid, the weaker the conjugate base. The weaker the acid, the strongerthe conjugate base.

Fill in the blanks in the table below.

Acid / Base / Equation
1. / H2SO4 / HSO4- / H2SO4↔H+ + HSO4-
2. / H3PO4
3. / F-
4. / NO3-
5. / H2PO4
6. / H2O
7. / SO4-2
8. / HPO4-2
9. / NH4+
10. / H2O

Bronsted-Lowry Acid Base Practice 2

Identify the acid, base, conjugate acid and conjugate base for each of the following.

a)HClO4(aq) + H2O(l) ⇄ H3O+(aq) + ClO4–(aq)

b)H2SO3(aq) + H2O(l) ⇄ H3O+(aq) + HSO3–(aq)

c)HC2H3O2(aq) + H2O(l) ⇄ H3O+(aq) + C2H3O2–(aq)

d)H2S(g) + H2O(l) ⇄ H3O+(aq) + HS–(aq)

e)HSO3–(aq) + H2O(l) ⇄ H3O+(aq) + SO32–(aq)

f)NH3(g) + H2O(l) ⇄ NH4+(aq) + OH–(aq)

g)HF(aq) + HSO3–(aq) ⇄ F–(aq) + H2SO3(aq)

h)HNO2(aq) + HS–(aq) ⇄ NO2–(aq) + H2S(aq)

Complete the equation for the reaction of each of the following with water. Indicate whether the ion or molecule is an acid or base, and whether Arrhenius, Bronsted-Lowry, or both explain each reaction.

a)HI(aq) + H2O(l)

b)HF(aq) + H2O(l)

c)C2H3O2–(aq) + H2O(l)
Name the following acids and bases:

1) NaOH______

2) H2SO3______

3) H2S______

4) H3PO4______

5) NH3______

6) HCN______

7) Ca(OH)2______

8) Fe(OH)3______

9) H3P______

11) H2CO3______

12) H2SO4______

13) HIO3______

14) HF______

15) HNO2______

Write the formulas of the following acids and bases:

16) hydrofluoric acid______

17) hydroselenic acid______

18) carbonic acid______

19) lithium hydroxide______

20) nitrous acid______

21) cobalt (II) hydroxide______

22) sulfuric acid______

23) beryllium hydroxide______

24) hydrobromic acid______

25) hydrocyanic acid ______

26) nitric acid______

27) sulfurous acid______

28) phosphorous acid______

29) acetic acid______

pH and pOH

The pH of a solution indicates how acidic or basic that solution is.

pH range 0 to-7 acidic

7 neutral

7-14 basic

Since [H+] [OH-] = 10-14 at 25 ˚C, if [H+] is known, the [OH-] can becalculated and vice versa.

pH = - log [H+] So if [H+] = 10-6 M, pH = 6.

pOH = - log [OH-] So if [OH-] = 10-8 M, pOH = 8.

Together,pH + pOH = 14.

Complete the following chart.

[H+] / pH / [OH-] / pOH / Acidic or Basic
1. / 10-5 M / 5 / 10-9 M / 9 / Acidic
2. / 7
3. / 10-4 M
4. / 10-2 M
5. / 11
6. / 12
7. / 10-5 M
8. / 10-11 M
9. / 13
10. / 6

pH and pOH practice 2

1) What is the pH of a 0.0235 M HCl solution?

2) What is the pOH of a 0.0235 M HCl solution?

3) What is the pH of a 6.50 x 10-3 M KOH solution? (Hint: this is a basic solution – concentration is of OH - )

4) What is the pH of a 6.2 x 10-5 M NaOH solution? (Hint: this is a basic solution – concentration is of OH - )

5) A solution with a H+ concentration of 1.00 x 10-7 M is said to be neutral. Why?

6) Find the pH of a 0.00476 M hydrochloric acid solution.

7) Find the pH of a solution that contains 3.25 g of H2SO4 dissolved in 2.75 liters of solution.

8) Find the pH of a 0.000841 M solution of sodium hydroxide.

9) If the pH is 9.85, what is the concentration of the aluminum hydroxide solution?

pH and pOH calculations 3

pH / [ H3O1+ ] / pOH / [ OH1– ] / ACID or BASE?
3.78
3.89 x 10–4 M
5.19
4.88 x 10–6 M
8.46
8.45 x 10–13 M
2.14
2.31 x 10–11 M
10.91
7.49 x 10–6 M
9.94
2.57 x 10–8 M
4.16
1.06 x 10–1 M
3.82
8.53 x 10–7 M
7.05
4.73 x 10–10 M
1.33
9.87 x 10–3 M
11.68
9.22 x 10–8 M
12.24
5.39 x 10–12 M

Acid-Base Neutralization Reactions

Neutralization is a chemical reaction between an acid and a base. Acids and bases are considered opposites because of their chemical behaviors. An acid has a pH of less than 7, and a base has a pH of greater than 7. A pH of 7 is considered neutral. Chemists say that an acid neutralizes a base when the two react completely, producing a salt (an ionic compound of a metal or positive ion bonded to a non metal ion) and water as products with a pH of 7. A neutralization reaction occurs in your stomach when you take an antacid (a base like tums, Pepto-Bismol) to neutralize your stomach acid and make you feel better.

Observe the teacher demonstration of hydrochloric acid, HCl, and sodium hydroxide, NaOH. Write the balanced chemical equation below. Name the products.

Directions: Write the balanced chemical equation for the following neutralization equations. Name the products

__H2SO4(aq) + __KOH(aq)  ______

___H3PO4(aq) + ___LiOH(aq)  ______

___H2CO3(aq) + __Mg(OH)2(aq)  ______

___H(C2H3O2)(aq) + __ NaOH(aq) ______

__HNO3(aq) + __Ca(OH)2 ______

__HBr(aq) + __KOH(aq)  ______