‫المملكة العربية السعودية‬
‫وزارة التعليم العالي‬
‫جامعة المجمعة‬
‫قسم الحاسب‬
Kingdom of Saudi Arabia
Ministry of Higher Education
Majmaah University
Computer Science Dept.
‫ قسم الحاسب‬:‫المستوى‬
‫ هـ‬1436/3/15 :‫تاريخ االمتحان‬
CHEM-225
:‫رقم ورمز المادة‬
‫ الكيمياء العامة‬:‫اسم المادة‬
:‫الرقم الجامعي‬
Answer the following questions:
Q1. Put circle around the correct answer of the following:
Elements are composed of extremely small particles called:
(a) atoms
(b) molecules
(c) ions
(d) compounds
According to Dalton, all matters consists of atoms which:
(a) extremely small particles
(b) indivisible particles
(c) invisible particle
(d) all
The subatomic particles which repel each other are
(a) electrons
(b) protons
(c) neutrons
(d) answers a and b
Atomic number is:
(a) the number of electrons
(b) the number of neutron in the
nucleus
(c) the number of protons in the (d) answers a and c are correct
nucleus
Electron configuration of sodium (atomic number=11) is:
(a) 1s2 1p2 2s22p5
(b) 1s2 2s22p53s2
2
2
6
1
(c) 1s 2s 2p 3s
(d) 1s1 2s32p63s1
Electron configuration of nitrogen (atomic number=7) is:
(a) 1s2 2s22p3
(b) 1s2 2s22p13s2
2
2
2
1
(c) 1s 2s 2p 3s
(d) 1s2 2s12p13s3
Covalent bond is formed between:
(a) Two non-metals
(c) metal and nonmetals
(b) Two metals
(d) all
Ionic bond is formed between:
(a) Two non-metals
(c) metal and nonmetals
(b) Two metals
(d) all
:‫اسم الطالب‬
Polar covalent bond such as:
(a) Cl-Cl
(c) MgCl2
(b) H-Cl
(d) NaCl
Non-polar covalent bond such as:
(a) Br-Br
(c) MgCl2
(b) H-Br
(d) NaCl
Q2. Solve of the following problems:
1. Calculate the number of moles in 3.01 × 1020 molecules of sulfur dioxide (SO2).
Answer:
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
2. A certain substance is found to contain 59.9% oxygen and 40.1% sulfur by mass.
What is the empirical formula of this substance?
(atomic weight for O = 16 , S = 32).
Answer:
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
3. A 250-ml flask, open to the atmosphere, contains 0.011 mol of air at 0 °C. Upon
heating, part of the air escapes; how much remains in the flask at 100°C?
Answer:
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
4. Calculate the mass percent of sodium chloride in a solution prepared by dissolving 24 g
of NaCl in 152 g of water.
Answer:
5. -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------5. Calculate the concentration of mercury as parts per million (ppm) in a
solution of 5 x 10-4 mg of mercury per 1 g water.
Answer:
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------6. Calculate the pH and pOH of an HCl solution which has a [H+] = 1.0 x 10-3
Answer:
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
7. Determine the equilibrium constant value (Kc) value for the following reaction , if
the concentration of each compound at equilibrium given as:
N2(g) + 3H2(g) ↔ 2NH3(g) at 500 K
[N2] = 3.0 x 10-2 M
[H2] = 3.7 x 10-2 M
[NH3] = 1.6 x 10-2 M
Answer:
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
8. Calculate Kp value For the following reaction:
N2(g) + 3H2(g) ↔ 2NH3(g) at 400 K
If the value of Kc was found to be 0.500
Answer:
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Q3-Complete the following
Element /Molecule
Oxidation no. of Al in Al2O3
Oxidation no. of C in CCl4
Oxidation no. of S in Na2SO4
Oxidation number
Class of chemical reaction
Example
Decomposition reaction
Single replacement reaction
Double replacement reaction
Combination reaction
2Na(s) + 2H2O (L)
Cu(s)
→ ---------------------------------------------
+ FeSO4 (aq) → ----------------------------------------------
Cl2(aq) + 2NaBr(aq) → ---------------------------------------------Good Luck