1. A week attraction between hydrogen atom in one molecule and an
oxygen in other called_______.
A. covalent bond
B. Hydrogen bond
C. Ionic bond
D. Metallic bond
Ans: B. Hydrogen bond
- Hydrogen bond only form between hydrogen and oxygen, nitrogen or
fluorine. Hydrogen bonds are very specific and lean to certain molecules having
special properties due to these types of bonds.
2. Which of the following substances is most likely a covalent compound ?
A. CaCO3
B. KNO3
C. SO2
D. NaOH
Ans: C. SO2
-Sulfur and oxygen are both non-metals which what form covalent
bond.
3. What is the element needed to bond with Na to create the most
ionic bond?
A. F
B. C1
C. Br
D. I
Ans: A. F
-When two atoms combine, the nature of the bond between them is
determine by the difference in their electronegativity. The choices belong to
Group VII-A. The arrangement of these elements in the periodic table indicate
that F (fluorine) being on top has the highest electronegativity. Therefore, it
can create the most ionic bond.
4. The boiling point of substance A is higher than that of
substance B. What does this meaning?
A. Substance A is less viscous than substance B.
C. Substance B has greater surface tension than substance A.
D. Substance B has weaker intermolecular forces than substance A.
Ans: D. Substance B has weaker intermolecular forces than
substance A.
-The boiling point of a compound is the temperature at which a
compound turns from a liquid to a gas or a gas to a liquid. This temperature is
a measure of the forces of attraction that exist between molecules in a
compound. The higher the intermolecular forces, the higher the boiling point.
5. What is the intermolecular force of attraction between the
nucleus of one atom and the electrons of a nearby atom?
A. Dipole-dipole force
B. Ion-dipole force
C. London dispersion force
D. Van der Waals force
Ans: C. London dispersion force
-All atoms and molecules combine have a weak attraction for the
one another known as van der Waals attraction. This attractive force has its
origin in the electrostatic attraction of the electrons of one molecule or atom
for the nuclei of another, and has been called London dispersion force.
6. Which of the following has the greatest number of atom?
A. Ca(OH)2
B. A12O3
C. NaHCO3
D. C2H2
Ans: C. NaHCO3
-Ca(OH)2 has 5 atoms, A12O3 HAS 5
ATOMS, NaHCO3 has 6 atoms and C2H2 has 4
atoms.
7. What does a
triangle , which is placed in a chemical
equation indicate?
A. Changes happened
B. Heat is applied
C. Gas is evolved
D. Precipitate
Ans: B. Heat is applied
- May mean
changes happened but not in a chemical equation. Triangle in a chemical
equation indicates that is applied to make the reaction proceed. Arrow down Is the symbol for evolution of gas. Arrow down Is the symbol to indicate precipitate
is formed.
8. What would most probably be the resulting chemical formula
when Mg+2and O-2combine?
A. MgO
B. Mg2O2
C. MgO2
D. Mg4O4
Ans: A. MgO
-Using criss-cross method combining Mg2+result tot Mg2O2
but it needs to be reduced to lower whole number ratio which is MgO.
9. Which of the following is an example of combustion reaction?
A. Mg+C12 -------------------------------------> MgC12
B. CaCO3 -------------------------------------> CaO
+ CO2
C. 2 C4H10 + 13
O2 ----------------------------------> 8
CO2 + 10 H2O
D. AgNO3 + NaC1 --------------------------------> AgC1 +
NaNO3
Ans: C. 2 C4H10 +
13 O2 ----------------------------------> 8 CO2 + 10 H2O
-A combustion reaction usually occurs
when a hydrocarbon react with oxygen to produce carbon dioxide and water. It is
an exothermic reaction so it releases heat.
10. What type of chemical reaction is
involved in Ca(S) + 2H2O Ca(OH)2(aq)?
A. Combination
B. Decomposition
C. Single-displacement
D. Double-displacement
Ans: C. Single-displacement
-Single displacement happens when one
element trades places with one another element in a compound. In the item,
hydrogen is replaced in water by
calcium forming a new compound plus hydrogen gas. Combination reaction occurs
when two or more simple compounds combine to form a more complicated one.
Decomposition happens when a complex molecule breaks down to make simpler ones.
Double displacement occurs when the anions and cations of two different
molecules switch places, forming two entirely different compounds.
11. When the fuel in a butane gas
stove undergoes complete combustion, it reacts with oxygen to form carbon
dioxide and water:_C4H10 + _ O2CO2+_H2O.
Which set of coefficients can be BEST used in balancing the equation?
A. 1, 1, 4, 2
B. 2, 2, 4, 5
C. 2, 8, 13, 10
D. 2, 13, 8, 10
Ans: D. 2, 13, 8, 10
- Reactions
Product
C= 2 x 4 = 8 C= 8 x 1 = 8
H= 2 x 10 =
20
H= 10 x 2 = 20
O= 13 x 2 =
26 O= 8 x 2
=16
O= 10 x 1 = 10
12. In oxidation-reduction, the
oxidizing agents is reduced and gains electrons. The reducing agent is oxidized
and loses electrons. Are the statements CORRECT?
A. Both statements are correct.
B. Both statements are false
C. First statement is true; second
statement is false.
D. Second statement is true; first
statement is false.
Ans: A. Both statements are correct.
- Oxidation-reduction (redox) involves
a transfer of electrons between two species. It is comprised of two parts, a
reduced half and an oxidized half, that always occurs together. The reduced
half gains electrons and the oxidation number decrease, while the oxidized half
losses electrons and the oxidation number increases. Simple way to remember
this is the mnemonic device OIL RIG meaning Oxidation Is Low Reduction is Gain.
13. How many moles of iron does 25 g
of Fe represent? (Fe=55.85 g)
A. 0.448 mol
B. 2.234 mol
C. 30.85 mol
D. 80.85 mol
Ans: A. 0.448 mol
-
(25 g) / ( 55.85 g/mol ) =0.448 mol
14. What is the mass of 5.0 mol of
water? (1 mol H2O=18.02g)
A. 3.60 g
B. 13.02 g
C.23.02 g
D. 90.10 g
Ans: C. 90.10 g
-(5 mol) (18.02 g/mol ) = 90.10 g
15. An analysis of salt shows that it
contains 56.58 g potassium; 8.68 g carbon and 34.73 oxygen. What is the
empirical formula of the substance?
A. KC2O3
B. K2CO2
C. K2CO3
D. K2C3O
Ans: C. K2CO3
-K (56.58 g) / ( 39.10 mol/g ) = 1.447
mol Divide the
result by the 2
C (8.68 g ) / ( 12.01 mol/g ) = .723 mol lowest answer
which 1
O (34.73 g) / (16 mol/g) = 2.171mol is .723 3
16. Which of the following is NOT a
principal assumption of Kinetic Molecular Theory?
A. Gas particles move rapidly.
B. Gases consists of submicroscopic
particles.
C. There is very little empty space in
a gas.
D. Gas particles have no attraction
for one another.
Ans: C. There is very little empty
space in a gas.
-Options A, B, and D are true. Gas
particles are much smaller than the distance between the particles. Most of the
volume of a gas is therefore empty space.
17. Based on the Kinetic Molecular Theory, a
gas can be compressed much more than a solid or liquid because__________.
A. gas particles move rapidly
B. the particles of a gas are very far
apart
C. a gas is composed do not attract or
repel one another
D. gas particles do not attract or repel one another
Ans: B. the particles of a gas are
very far apart
-Sold are difficult to compress as the
particles are already paced closely together. Liquids are difficult to compress
because there are quite a lot of particles in small volume. Gases are easily
compressed because there are only few particles in a large volume.
18. Which refers to the kinetic energy
or motion of gas particles?
A. Pressure
B. Quantity of gas
C. Temperature
D. Volume
Ans: C. Temperature
-An input of heat can cause an
increase in temperature because the input of heat is realized as an increase in
the kinetic energies of the gas molecules. When the average kinetic energy of
the gas molecules goes up, the temperature goes up.
19. A given mass of gas has a volume
of 750 ml at -25℃ and 280
torr. What would the volume of the gas be at 30
and 560 torr of pressure considering the
amount of gas which is constant?
and 560 torr of pressure considering the
amount of gas which is constant?
A. 450
ml
B. 458 ml
C. 480 ml
D. 520 ml
Ans: B. 458 ml
This item
involves combined gas law : P1V1 = P2V2
T1 T2
20. Seven liters of an ideal gas are
contained at 3.5 atm and 30
How many moles of this gas are
present?
How many moles of this gas are
present?
A. 0.50 mol
B. 0.75 mol
C. 1.00 mol
D. 1. 25 mol
Ans:
C.
1.00 mol
- n=PV/RT
n= (3.5
atm x 7 L ) / (.08 L atm/mol K x 303 K) = 1.00 mol
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