Hariri High School II
Term II Chemistry Test
Date: March 7th, 2011
Time: 60 min.
Name: _______________
Grade 10 (A, B & C)
Remark: Molar masses of different elements are given at the end of the test.
First Exercise
Ionic Compounds
Applying Knowledge
A mixture (M) is prepared by adding together 10.15g of NH4ClO3 and (X) formula units (f.u.)
of Ag2HSO4. The total number of oxygen atoms in the mixture (M) is 5.7x1023 atoms.
A.
B.
C.
D.
Name each of the ionic compounds NH4ClO3 and Ag2HSO4. (1 pt.)
Draw the Lewis structural formula of each of the above two compounds. (1.5 pts.)
Indicate the VSEPR type of Cl in ClO3-. (1 pt.)
Find (X) the number of f.u. of Ag2HSO4. (2 pts.)
Second Exercise
Chemical Reactions
Applying Knowledge
Parts A & B are independent.
A. Complete and balance each of the following reactions, if any. Then, Write the
corresponding net ionic equation when possible. (3.75 pts.)
1. Decomposition of zinc bicarbonate
2. NaCH3COO + Ba
3. Phosphoric acid + magnesium sulfite (aq)
4. Tin chloride + iodine crystals
B. When 0.2 moles of a hydrocarbon CxHy burns completely, 13.44 L of CO 2 gas is
evolved at STP, and 14.4 g of water is formed.
1. Write the balanced equation of the above reaction in terms of x and y. (1 pt.)
2. Calculate x and y. Deduce the molecular formula of the hydrocarbon. (2 pts.)
3. The CO2 gas produced in the above reaction is bubbled in lime water.
a. Calculate the mass of the precipitate formed. (2.25 pts.)
b. What is the type of this reaction? (1 pt.)
Third Exercise
Thermochemistry
- Applying Knowledge
- Mastering Communication Techniques
Consider the reaction A + 2B → C.
In this reaction, the total energy of the reactants (HR) is 80 kJ; the total energy of the products
(HP) is -90 kJ and the activation energy (Ea) for the reaction is 50 kJ.
A. Draw a labeled energy profile for the above reaction. (1.5 pts.)
Take the scale: y- axis: 20 KJ →1 cm .
B. Is the above reaction endothermic or exothermic? Justify. (1 pt.)
C. Calculate the heat change (ΔH) of the above reaction. (1 pt.)
D. Calculate the amount of heat produced when half a mole of B is consumed. (1 pt.)
Given: M(N) =14g.mol-1 – M(H) = 1 g.mol-1- M(Cl) =35.5 g.mol-- M(O) = 16 g.mol-1
M(Ca) = 40 g.mol-1 – M(C ) 12 g.mol-1