QUESTIONS OF MID SEMESTER
SUBJECT : CHEMISTRY
CLASS : SENIOR
2
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Num.
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Topic
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Question
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Answer key
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Level of difficulty
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1
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Fundamental concepts of chemistry
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The Simplest substances and are composed of
a single type of atom are called..
a.
The
Chemical elements
b.
The
Compound
c.
Molecules
d.
Metals
e.
Non-metals
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A
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Medium
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2
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Atomic structure
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An atom of aluminium has mass number 27 and
atomic number 13. Which statement is true..
a.
Proton 13,
electron 13, neutron 14
b.
Proton 27,
electron 14, neutron 13
c.
Proton 13,
electron 27, neutron 14
d.
Proton
14,electron 13, neutron 14
e.
Proton 13,
electron 14, neutron14
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A
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Medium
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3
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The mole concept and Avogadros’s constant
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The mole of magnesium that can be obtained
from the reaction between 9.6 grams of magnesium and 9.8 gram sulfur. (Ar Mg = 24, S= 32)
a.
0.1 mol
b.
0.2 mol
c.
0.3 mol
d.
0.4 mol
e.
0.5 mol
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D
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Medium
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4
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Ionic equation
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The Ionic equation of MgSO4 is..
a.
Mg + SO4
b.
Mg+ + SO4-
c.
Mg+ + SO42-
d.
Mg2+
+ SO42+
e.
Mg2-
+ SO42+
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D
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medium
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5
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The ideal gas equation
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What is the volume of 4 gram hydrogen gas at 270C temperature and 1 atm pressure.
a.
44,1 L
b.
45,2 L
c.
46,3 L
d.
48,2 L
e.
49,2 L
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E
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Difficult
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6
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Empirical and molecular formula
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A Compound containing 46,2 % by mass of
carbon, and 53,8% by mass of Nitrogen in STP condition. If the volume of this
gas is 5,6 Litre and its mass is 13 gram, what is the formula of the
compound.? ( Ar C = 12, N = 14)
a.
CN
b.
CN2
c.
C2N
d.
C2N2
e.
C2N4
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D
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Difficult
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7
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Ionic
bonding
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Which one of the following compounds is classified to ionic compound..
a.
HCl
b.
NaCl
c.
CO2
d.
N2
e.
CH4
|
B
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Difficult
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8
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Covalent bonding
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The groups of compounds below which are
having a covalent bond are..
a.
KCl, HBr,
Cl2
b.
I2
, HBr, KCl
c.
CO2,
CH4 ,NaCl
d.
NaH, KBr,
LiCl
e.
NH3,
H2O , HCl
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E
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Medium
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9
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Calculation
of Enthalpy changes
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The reaction of CO2 gas formation
occurs in two steps, those are ;
C(s) +
 O2(g)
à CO(g) ∆H = -110 kJ
CO(g) +
O2(g)
à CO2(g) ∆H =
-284 kJ
What is the change in enthalpy for reaction
of CO2 gas formation.
a.
-694 kJ
b.
-594 kJ
c.
-394 kJ
d.
-294 kJ
e.
-194 kJ
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C
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Difficult
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10
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The periodic table
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Element which doesnot belong to earth
alkaline group, is..
a.
Mg
b.
K
c.
Ba
d.
Sr
e.
Ca
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B
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Medium
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11
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Physical properties of elements
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The minimum energy required to remove one
mole of electron from one mole of gases atoms is called…
a.
The first ionization
energy
b.
The
electronegativity
c.
The
melting point
d.
The
density
e.
The alkali
metals
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A
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Easy
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12
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Solutions
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What is the concentration of 0.98 gram H2SO4 ( molar
mass =98) in 500 ml water.
a.
0.08 mol/L
b.
0.06 mol/L
c.
0.04 mol/L
d.
0.02 mol/L
e.
0.012
mol/L
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D
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Medium
|
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13
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Atomic structure
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Electrons occupy regions of space known as….
a.
Shell
b.
Orbital
c.
Quantum number
d.
Element
e.
Table periodic
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B
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Easy
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14
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Atomics radius
|
The distance of the outer electron from the nucleus known as…..
a.
Nuclear charge
b.
Shielding effect
c.
Atomic radius
d.
Ionization energy
e.
Electron
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C
|
Medium
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15
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Trends across period 3
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The products of this reaction is…….
Na2O(s) + 2HCl à………..
a.
2NaCl
+ H2O
b.
2NaCl2 + H2O
c.
2NaCl
+ H2O2
d.
2Na2Cl + H2O
e.
2NaCl2 + H2O2
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A
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Difficult
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16
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Oxides of periode 3
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The products of this reaction is…….
MgO(s) + H2O(l)
à……..
a.
Mg(OH)2 (aq)
b.
Mg2(OH)2 (aq)
c.
Mg3(OH)2 (aq)
d.
Mg4(OH)2 (aq)
e.
Mg5(OH)2 (aq)
|
A
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Difficult
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17
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hybridization
|
The hybridization of BeCl2 is…….(
atomic number of Be = 4 and Cl = 17)
a.
Sp
b.
Sp2
c.
Sp3
d.
Sp3d
e.
Sp3d2
|
A
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Medium
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18
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hybridization
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The hybridization of BF3 is…….(
atomic number of B = 5 and F = 9 )
a.
Sp
b.
Sp2
c.
Sp3
d.
Sp3d
e.
Sp3d2
|
B
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Medium
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19
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Hybridization
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The hybridization of CH4 is…….(
atomic number of = 6 and H = 1 )
a.
Sp
b.
Sp2
c.
Sp3
d.
Sp3d
e.
Sp3d2
|
C
|
Medium
|
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20
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enthalpy
|
Given that reaction
N2(g) + 3H2(g) à 2NH3(g) ∆H = -34 kJ
The heat released when 56 grams of nitrogen
gas reacts is ……( Ar N = 14)
a.
34 kJ
b.
68 kJ
c.
102 kJ
d.
136 kJ
e.
170 kJ
|
B
|
Difficult
|
|
21
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Enthalpy
|
Magnesium is burned to produce 1 gram of MgO
and heat of 14,4 kJ, then the change in enthalpy of MgO formation is…….
a.
-44.4 kJ
b.
+44.4 kJ
c.
-288 kJ
d.
-576 kJ
e.
+1.122 kJ
|
D
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Difficult
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22
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Bonding
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Which type of bond id formed by the sideways
or lateral overlap of p orbital?
a.
Pi bond
b.
Dative bond
c.
Ionic bond
d.
Sigma bond
e.
Covalent bond
|
A
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Medium
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23
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Pi and sigma bond
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Which of the following molecules does not
have a Pi bond?
a.
CO2
b.
CO
c.
N2
d.
H2O2
e.
SO3
|
D
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Difficult
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24
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Enthalpy change
|
The enthalpy change which takes place when
one mole of gaseous atoms is formed from the element in its standard state
under standard conditions, known as……
a.
The standard enthalpy change of reaction
b.
The
standard enthalpy change of combustion
c.
The
standard enthalpy change of solution
d.
The bond
enthalpy
e.
The
standard enthalpy change of atomization
|
E
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Medium
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25
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Kinetics
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The reaction of ;
2NO +
Cl2 à 2NOCl has the reaction
rate equation
V = k[NO]2[Cl2]
If at constant temperature, the
concentration of NO is decreased to ½ times , while the contration of Cl2
is constant ,the reaction rate is….
a.
2 times than initial
b.
½ times than the initial
c.
4 times than the initial
d.
¼ times than the initial
e.
Contestant
|
D
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Difficult
|
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Num.
|
Topic
|
Question
|
Answer key
|
Level of difficulty
|
|
1
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Ionization energy
|
The minimum energy per mole required to remove electron from one mole
of isolated gaseous atoms to form one mole of gaseous unipositive ions under
standard thermodynamic conditions, known as……
|
Ionization energy
|
Medium
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2
|
Nuclear charge
|
The force that attracts all the electrons to the nucleus, known as…..
|
Nuclear charge
|
Medium
|
|
3
|
Chlorides of periode 3
|
The product of the chlorides of phosphorus reaction is…….
PCl3(l) + 3H2O(l) à…………………
|
H3PO3(aq +
3HCl(aq)
|
Medium
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|
4
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Chloride of period 3
|
The product of the silicon tetrachlore reaction is…….
SiCl4(l + 2H2O(l)
à
…………
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SiO2(s) + 4HCl(g)
|
Medium
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5
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Enthalpy
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The standard enthalpy change of reaction is………….
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The enthalpy change which take place when the reactants in the
balanced chemical equation react together under standard thermodynamic
conditions to give the products.
|
Difficult
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6
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Energetics
|
The type of bond that arises from the attraction between oppositely
charged ions in a lattice, known as……………
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Ionic bonding
|
Medium
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7
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Enthalpy change
|
The enthalpy change which takes place when one mole of a solute
dissolves to form an infinitively dilute solution, known as……………
|
The standard enthalpy change of solution
|
Medium
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|
8
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The spontaneous of reaction
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In a temperature, The Gibbs free energy change has the positive sign, it means that………
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The reaction isnot spontaneous at this temperature
|
Medium
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9
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Kinetics
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The rates of many reaction are affected by………….
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Changes in the concentration of their reactants
|
Medium
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10
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Kinetics
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A precise mathematical way to summarizing this information about
concentration changes, known as………..
|
The rate expression
|
Medium
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Num.
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Topic
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Question
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Answer key
|
Level of difficulty
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||||||||||||||||
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1
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Energitics
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What is exothermic and endothermic reaction, and example reaction for
each reaction?
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Exothermic reaction is the majority of chemical reactions release
heat energy to their surroundings
Example :
CH4 + O2 à
CO2 + H2O ∆H
= - X kJ
Endothermic reactions are a few chemical reactions absorb heat energy
from their surroundings
Example
CaCO3 à
CaO + CO2 ∆H = + X kJ
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Difficult
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||||||||||||||||
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2
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Enthropy change
|
Calculate the entropy change that occurs during the complete
combustion of methan.
CH4 + 2O2 à
CO2 + 2H2O
Ṧ[CH4]
= 200 J/Kmol
Ṧ[O2]
= 100 J/Kmol
Ṧ[CO2]
= 400 J/Kmol
Ṧ[H2O]
= 50 J/Kmol
|
∆Ṧ
= ∑ Ṧproduct - ∑ Ṧreactant
∆Ṧ = [(400)+(2x50) – (200)+ (2x100)]
∆Ṧ
= 100 J/Kmol
|
Difficult
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||||||||||||||||
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3
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Spontaneity of reaction
|
Dertermine whether the following reaction occurs spontantly or
unspontatly?
N2(g) + 3 H2(g) à
2NH3(g) ∆H = 95.4 kJ/mol ; ∆Ṧ
= -198.3 kJ/Kmole and T = 270C
|
∆G
= ∆H – T (∆Ṧ)
∆G = -95.4 kJ/mole – ( 300)
(-0.1983 kJ/Kmole
∆G
= -95.4 kJ/mole – (-59.49)
= -35.91 kJ/mole
The negative sign indicates that the reaction is spontaneous at this
temperature
|
Difficult
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||||||||||||||||
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4
|
Kinetics
|
An experiment is conducted to observe a reaction of :
2NO + 2H2 à
N2 + 2H2O
a. Reactions
orders
b. The
reaction rate equation
|
a.
The reaction order with respect to NO
At constant . if
(NO) is increased 4 times, the reaction rate increases of 32 times
  k1 = k2 
For the reaction
order with respect to H2
With the same
way, we got that n= 2
Thus, the
reaction rate equation is..
V = k[NO]5/2[H2]2
|
Difficult
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||||||||||||||||
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5
|
Reaction rate
|
Write down the factors influencing
reaction rates
|
1.
Surface area
2.
Temperature
3.
Concentration
4.
Pressure
5.
Catalyst
|
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