Download The Islamic University of Gaza

The Islamic University of Gaza
General Chemistry (CHEMA 1303)
Chemistry Department
Time: 1 hour
Date : 2.12.2007 ‫األحد‬
.........................................................:‫االسم‬
‫ نظام‬.‫د‬
‫ فخر‬.‫د‬
‫ ماجد‬.‫ زياد د‬.‫ د‬:‫المدرس‬
25
....................................
:‫الرقم الجامعي‬
: ‫الشعبة‬
101,102, 103 ***** 201, 202, 203, 204, 205
I) Indicate if the following statements are True ( T ) or False (F)
(
(
(
(
(
(
)
)
)
)
)
)
(1/2 mark each)
1- Sodium sufide, Na2S is expected to dissolve in water
2- NH3 is the conjugate base of nitrous acid, HNO2
3- The oxidation number of Cr in dichromate ion Cr2O7 2- is +3
4- The reaction between Mg and HCl acid is an oxidation- reduction reaction
5- When water forms from H2 and O2 gases, E and H are equal for this reaction
6- The electron configaration of Cr ( z = 24 ) is [Ar]4s2 3d4
II) Choose the correct answer:
(1 Mark each)
1. One of the followings is not a state function.
a.Heat
b. Enthalpy
c.Internal energy
d. Potential energy
2. The main device used in gravimetric analysis is
a. buret
b.Balance
c. Flame
d. Calorimeter
3- Which of the following is not a possible valu e of mℓ for an electron of ℓ = 2
a. 0
b.+3
c.-1
d.2
4. When adding 50 mL of water to 50 mL of 0.1 M NaCl solution the number of moles of NaCl
will
a.Increase
b.Decrease
c.unchanged
d. None of mentioned
5. A neutral atom of the element that has atomic number 17 has _____ valence electrons
a. 1
b. 3
c. 5
d. 7
6- Which of the following electron configurations represents a ground state of a neutral atom?
a.[Ne] 3s1 3p1
b. [He] 2s1 2p3
c.[Ne] 3s2 3p3
d. [Ne] 3s2 3p3 3d1
III) Choose the correct answer: (Showing the solution for each) (2 Marks each)
1- The molarity of 85.0 mL solution contains 1.77g ethanol ( MWt = 46.0 ) in water is
a. 0.144 M
b. 0.561 M
c. 0.452 M
d. 6.174 M
2- The density of a gaseous compound is 3.38 g/L at 40oC and 1.97 atm. .So the molar mass of the
compound will be,
a.33.8 g/mol
b.180 g/mol
c.77.2 g/mol
d. 44.1 g/mol
3- When a 25.0-g block of aluminum absorbs 10.0 kJ of heat, its temperature will rise how many
degrees? The specific heat of Al is 0.900 J/ºC.g
a. 444oC
b. 225oC
c. 22.5oC
d. 360oC
4- If 1.0 L of H2 gas was mixed with 1.0 L O2 gas at 120oC and 1.0 atm., the volume of water vapor
produced at the same conditions will be,
a.1.0 L
b.2.0 L
c.3.0 L
d.1.5 L
2
5- For the reaction,
N2 (g ) 3 H2 (g) 
2 NH3 (g)
H = - 92.6 kJ
4
so, heat released when 1.26 x 10 g NH3 produced at constant pressure will be as
a. – 185.2 kJ
b. – 2.24 x 103 kJ
c. – 3.43 x 104 kJ
d. – 1.24 x 104 kJ
6- How many molecules of O2 are there in 1.0 L air at STP ? O2 is 21% of air by volume
( Avog. No. = 6.022 x 1023 )
a. 2.2 x 1020
b. 3.24 x 1019
c. 5.65 x 1021
d. 1.24 x 1041
7- If a compound A, converts to compound B with H = - 10 kJ, and compound B, converts to
compound C with H = - 20 kJ, then if compound C, converts to A, so H of this change will be
a. – 10 kJ
b.+ 10 kJ
c. – 30 kJ
d. + 30 kJ
8- Balance the following equation, then write the ionic and net ionic equations
Mg(NO3)2 (aq)
+ NaOH(aq)

Mg(OH)2
+
NaNO3
3
1- If a compound A, converts to compound B with H = - 10 kJ, and compound B, converts to
compound C with H = - 20 kJ, then if compound C, converts to A, so H of this change will be
2- When a 25.0-g block of aluminum absorbs 10.0 kJ of heat, its temperature will rise how many
degrees? The specific heat of Al is 0.900 J/ºC.g
4