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NCFE Mock Chemistry Final Exam Flashcards | StudBud
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NCFE Mock Chemistry Final Exam
NCFE Mock Chemistry Final Exam
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A mock #finalexam to help students prepare for the #NCFE #chemistry final
Flashcards
31 cards
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Practice quiz
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Questions
31
Answers
1
Which isotope has the greatest number of protons?
U-240
Pu-239
Np-238
Pa-238
2
In order to neutralize a small amount of ammonia. Which substance would be
best
to use?
lemon juice
milk
drain cleaner
water
3
Which is a formula for an ionic compound?
SF4
BF3
LiCl
CCl4
4
Which statement describes what happens to Mg and O when they chemically combine?
Mg gain 2 e- to form an anion, O lose 2 e- to form a cation
Mg lose 2 e- to form an anion, O gain 2 e- to form a cation
Mg lose 2 e- to form an cation, O gain 2 e- to form a anion
Mg gain 2 e- to form an cation, O lose 2 e- to form a anion
5
A piece of wood will burn more vigorously in pure oxygen than in air. Why?
The O2 is a catalyst and increases the rate of the reaction.
The O2 and CO2 produced reach equilibrium.
The O2 and N2 present in air inhibit the burning of the wood
The O2 is required for the combustion of the wood.
6
What is the empirical formula of the compound?
Ca2OH2
CaO2H2
Ca2OH
CaO3H3
7
A gas has a pressure of 1.3 atm at 450 K. Then decreases to 270 K, what is the final pressure?
1.70 atm
2.20 atm
0.78 atm
0.45 atm
8
Based on the VSEPR theory, what is the molecular geometry of CBr
4
?
trigonal planar
trigonal pyramidal
linear
tetrahedral
9
How are the bonds formed in a polar covalent compound?
Electrons are gained.
Electrons are lost.
Electrons are shared unequally.
Electrons are shared equally.
10
Which describes a proton?
a + charged particle that is more massive than an electron.
a + charged particle that is less massive than an electron.
a - charged particle that is more massive than an electron.
a - charged particle that is less massive than an electron.
11
How many protons and electrons are present in a barium
117
56
Ba
2+
ion?
56 protons, 56 electrons
54 protons, 56 electrons
54 protons, 54 electrons
56 protons, 54 electrons
12
What is the temperature of 1.4 mol of a gas with a pressure of 3.25 atm in a 4.738 L container?
130 K
180 K
150 K
170 K
13
Why is sodium chloride soluble in water, but insoluble in benzene?
water has polar molecules and benzene has nonpolar molecules
water boils at a higher temperature than benzene at STP
sodium and water are both ionic compounds
NaCl chloride is a covalent and benzene is ionic
14
Which element is a halogen?
mercury
sodium
helium
chlorine
15
Which bond is strongest?
The bond between F and F in a F2 molecule
The bond between C and F in a CF molecule
The bond between H and F in a HF molecule
The bond between O and F in a OF2 molecule
16
How does an atom become chemically stable?
by increasing the electronegativity of each atom
by increasing the polarity of the orbitals of each atom
by allowing more e- of each atom to enter excited states
by gaining or losing electrons in certain energy levels
17
In 75.0 grams of water, how much potassium chlorate will dissolve at 50.0
o
C?
10.0 g
15.0 g
30.0 g
13.3 g
18
What can the student conclude about the experiment?
A chemical reaction occurred because new atoms were created.
The popping sound proves the acid changed physical states.
A chemical reaction occurred b/c a new substance was formed.
The popping sound proved the magnesium atoms were destroyed.
19
At which phase change would atoms have the least kinetic energy?
boiling
sublimation
condensation
freezing
20
How much heat energy is required to raise the temp. of 25 grams of water from 20.
o
C to 45.
o
C?
4,700 J
2,600 J
2,100 J
1,600 J
21
Based on the elements in Group 2 of the periodic table, what do these elements have in common?
the ratio of protons to neutrons
the number of occupied energy levels
the number of valence electrons
the total number of neutrons
22
What is the concentration of hydroxide ions, [OH
-
], in a neutral solution?
7 M
1 x 10-14 M
14 M
1 x 10-7 M
23
What is the name of the compound with the chemical formula CoF
3
?
cobalt trifluoride
fluorine(III) cobalt
cobalt(III) fluoride
fluorocobalt
24
How many grams of hydrogen are in 3.0 moles of NH
4
OH?
12 g
15 g
4.0 g
5.0 g
25
Red litmus paper turns blue when a drop of solution is placed on it. Which is a true statement?
There are only hydronium ions in the solution
There are only hydroxide ions in the solution
The [OH-] in the solution is greater than the [H+]
The [H+] in the solution is greater than the [OH-]
26
What is the percent composition of carbon in CO
2
?
33%
10%
27%
43%
27
Fe
2
O
3
is heated at a high temperature to form Fe and O
2
. Which chemical reaction type occurred?
combustion
synthesis
single replacement
decomposition
28
How many O
2
particles are in 2.50 moles of O
2
at Standard Temperature and Pressure (STP)?
1.51 x 1024 particles
2.41 x 1023 particles
5.02 x 1023 particles
4.15 x 1022 particles
29
What is the correct chemical formula for the result of a chemical reaction between Na and O
2
?
Na2O
NaO2
NaO3
NaO
30
A solution has a hydrogen ion concentration of 1.0 x 10
-6
M. How is this solution classified?
as an acid, because it has a pH of 3
as a base, because it has a pH of 12
as a base, because it has a pH of 8
as an acid, because it has a pH of 6
31
How many moles are present in 4.50 L of F
2
at Standard Temperature and Pressure (STP)?
101 moles
85.5 moles
0.201 mole
0.237 mole
