King Abdulaziz University

Faculty of Science - Chemistry Department - Dr : Mohamed KH

Chem-110, First Exam

Wednesday 22 /06
/1440 H

Time: 90 minutes
Name: Number: Section:

●Useful information:
Speed of light, C = 3.0×108 m/s
Planck’s const., h = 6.626×1034 J.s
Avogadro’s No., Nav = 6.022×1023 mol1
Rydberg const. for H atom RH = 2.18 ×1018 J
Mass of the electron, me = 9.11 x 1031 kg
Gas constant, R = 0.082 L atm K1 mol1
1A 8A
1 4
H
Hydrogen
PERIODIC TABLE He
Helium
1 2A 3A 4A 5A 6A 7A 2
Key Relative atomic mass to
7 9 nearest whole number 11 12 14 16 19 20
Li Be 12 B C N O F Ne
Lithium Beryllium Boron Carbon Nitrogen Oxygen Flourine Neon
3 4 C Symbol 5 6 7 8 9 10
Carbon
23 24 6 Atomic number 27 28 31 32 35.5 40
Na Mg Al Si P S Cl Ar
Sodium Magnesium Aluminum Silicon Phosphorus Sulfur Chlorine Argon
11 12 13 14 15 16 17 18
39 40 45 48 51 52 55 56 59 59 63.5 65 70 72.5 75 79 80 84
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
85.5 86 89 91 93 96 (96) 101 103 106 108 112 115 119 122 128 127 131
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
133 137 139 178.5 181 184 186 190 192 195 197 201 204 207 209 (210) (210) (222)
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Cesium Barium Lanthanum Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine Radon
55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86

(223) (226) (227) (261) (262) (266) (264) (265) (268)

Fr Ra Ac Rf Db Sg Bh Hs Mt
Francium Radium Actinium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium
87 88 89 104 105 106 107 108 109

140 141 144 145 150 152 157 159 162.5 165 167 169 173 175
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium
58 59 60 61 62 63 64 65 66 67 68 69 70 71
232 231 238 237 244 (243) (247) (247) (251) (252) (257) (258) (259) (262)
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium
90 91 92 93 94 95 96 97 98 99 100 101 102 103
 Ch15 : ACIDS AND BASES
Acid: substance give hydrogen ions [H+] when dissolves in water

Ex: HCl (aq) H (aq) + Cl (aq)

Base: substance give hydroxide ions [OH ] when dissolves in water.

Ex: NaOH(aq) Na (aq) + OH (aq)

Acid and base neutralize each other

H (aq) + OH (aq) H 0(l)

The most acidic solution is

a) pH = 6 b) pH = 4 c) pOH = 9 d) pOH = 12

ex: The least acidic solution is

a) pH= 6.5 b) pH= 2 c) pH= 3.5 d) pH = 1

ex: The most basic solution is

a) pH =8 b) pH =7.5 c) pOH = 3 d) pOH = 5

ex: The least basic solution is

a) [H]=1x10 b) [H]=1x10 c)[H]=1×10 d) [H] = 1×10

EX: for solution having POH 7

a) [H] 10 b) [OH] 10 c) [H] 10 d) It is basic solution

ex: Calculate [OH] , pH and pOH of HCl solution has [H]= 0.02M

Strong acids : complete dissociation

ex: HCI, HNO , H ,SO , HBr, HI , HCIO

HCl (aq) H (aq) + Cl (aq)

Strong bases : complete dissociation

ex: LiOH, NaOH , KOH , Mg(OH) , Ca(OH) , Ba(OH)

NaOH(aq) Na(aq) +OH (aq)

ex: What is pH of 0.02 M H SO solution?

ex: What is the concentration of hydrogen ion in 2x 10 M KOH

solution?
ex: Calculate pH of solution prepared by dissolving 0.63 g of Nitric
acid HNO ; in 500 ml solution.

ex: Calculate the mass of NaOH require to prepare 200 ml of

solution has pOH = 4? (pH =10)
 Weak acids : partial dissociation

ex: Calculate pH of 0.08 M acetic acid solution Ka = 1.8 x 10 ?

ex: What is the "Ka'' of 0.1 M formic acid solution has pH = 2.3
ex: Calculate pH of 0.1 M HF solution 8.4% lonized ?

ex: calculate the ionization percent of 0.1 M of HF solution has

pH = 2.1?
Ex: what is the ionization percent of 0.01M HF solution has
K = 3.2x10

Weak base : partial dissociation

Ex: ammonia NH3 , ammonium hydroxideNH OH

Ex: calculate the pH of 2.0 M ammonium hydroxide has Kb=1.8x10 ?

The Common lon Effect

The presence of common ion suppresses the ionization of a weak acid

or a weak base.

So the common ion effect is a special case of Le Chatelier's Principle

Buffer Solutions:-

Solutions have the ability to resist changes in pH on the addition of

small amount of either acid or base.

A buffer solution is (1) Weak acid and its salt

(2) Weak base and its salt
 ex;- Which one of the following is a buffer solution?

a) 1.0M HNO and 1.0M NaNO b) 0.20M CH COOH

c) 0.4M CH COOH and 0.1M CH COO d) O.1M HF and 0.3M NaBr

ex:- Which one of the following is a buffer solution?

a) HBr/KBr b) HNO / NaNO

c) HF/ KF d) HI /KI
How does the buffer solution resist the change in PH

If buffer solution consists of weak acid and its conjugate base

When base is added the weak acid will neutralize it and if acid is added
the conjugate base will neutralize it

Ex: CH COOH / CH COONa

CH COONa(s) CH COO (aq) + Na (aq)

When acid is added the conjugate base CH COO will be neutralize the
H according to the equation

CH COO (aq) + H (aq) CH COOH(aq)

When base is added the acid CH COOH will be neutralize the OH

according to the equation

CH COOH (aq) + OH (aq) CH COO (aq) +HO

Blood buffer system

-Blood contains a buffer solution of carbonic acid (H CO ) and

bicarbonate (HCO ) maintaining blood pH between 7.35 and 7.45
- A value of blood pH higher than 7.8 or lower than 6.8 can lead to death

H O + HCO H CO + H O

H CO H O+ CO
1- The pH of a solution is 0.78. What is the [H] ?

a) 0.78 M b) 0.17 M c) 0.11 M d) 2x10

2- Calculate the pH of a 6.71x10 M NaOH solution.

a) 12.83 b) 2.17 c) 11.82 d) 6.71

3- What is the pH of a 0.014 M Ca(OH) solution?

a) 1.85 b) 1.55 c) 12.15 d) 12.45

4- The OH concentration in a 1.0x 10 M Ba(OH) solution is

a) 0.50 x 10 M b) 1.0 x 10 M c) 2.0 x 10 M d) 1.0 x 10 M

5- Which of the following statements is true concerning acids and bases?

a) acids and bases don't react with each other.
b) acids mixed with bases neutralize each other.
c) acids mixed with bases make stronger bases
d) acids mixed with bases make stronger acids.

6- A 0.14M HNO solution is 5.7% ionized. Calculate the H ion

concentration.

a) 8.0 x 10 M b) 0.057 M c) 0.13 M d) 0.080 M

7-Which of the following solutions has the lowest PH ?

a) 0.3 M HCI b) 0.3 M NaOH c) pure water d) 0.3 M NH

8- The percent ionization of 0.3M hydronuorie acid Ka = 6.2 x 10

is......... And it is..........acid
a) 22% , strong b) 22% , weak c) 4.5% , strong d) 4.5% , Weak

9-Which one of the following is a buffer solution?

a) 1.0M HNO and 1.0M NaNO
b) 0.4M CH COOH and O.IM CH COO
c) 0.20M CH COOH

10- substance gives hydrogen ions when dissolved in water?

a) base b) Acid c) butter solution d) [H]

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