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WorksheetsChemistry NCFE Released Questions
Total questions: 40
Worksheet time: 3hrs 20mins
1) Which isotope has the greatest number of protons?
Pa-238
U-240
Np-238
Pu-239
2) A neutral atom of a certain element has the electron configuration 1s22s22p63s23p4. How many valence electrons does the atom have?
4
6
11
16
3) What color of light does a hydrogen atom emit when an electron transitions from the n=6 energy level to the n=2 energy level?
orange
yellow
blue
violet
4) The equation below represents the radioactive decay of a gold isotope.
174 79 Au →17077 Ir + ?
Which choice correctly completes this equation?
alpha particle
beta particle
photon
neutron
5) A neutral atom has a ground state electron configuration of 1s22s22p63s2. The neutral atom becomes an ion during a chemical reaction. Which is the most likely charge of the ion?
2+
1+
2-
6-
6) How many electrons are in the outermost energy level of a neutral carbon atom?
2
4
6
8
7) The compound sodium chloride is placed in water and separates into ions. What are the correct names for these ions?
The chloride and sodium ions are cations.
The chloride and sodium ions are anions.
The sodium ion is the anion, and the chloride ion is the cation.
The sodium ion is the cation, and the chloride ion is the anion.
8) Which element will form covalent bonds with chlorine?
carbon
aluminum
magnesium
potassium
9) Which type of bonding or intermolecular forces is/are weakest?
London dispersion forces
hydrogen bonding
dipole-dipole forces
covalent bonding
10) What is the chemical formula for chromium(III) oxide?
CrO
CrO2
Cr2O3
Cr3O2
11) Based on the information in the table, what can be concluded?
Both solids contain only ionic bonds.
Both solids contain only covalent bonds.
Solid X contains only covalent bonds, and Solid Y contains only ionic bonds.
Solid X contains only ionic bonds, and Solid Y contains only covalent bonds.
12) What is the name of the compound with the chemical formula CoF3?
fluorocobalt
cobalt trifluoride
cobalt(III) fluoride
fluorine(III) cobalt
13) Which statement best compares how bond strengths affect the physical properties of iron and lead?
Iron has a higher melting point because the bonds in iron are stronger.
Iron has a higher melting point because the bonds in iron are weaker.
Lead has a higher density because the bonds in lead are stronger.
Lead has a higher density because the bonds in lead are weaker.
14) How is copper (Cu) classified based on its location on the periodic table?
a nonmetal
an alkaline earth metal
a transition metal
an alkali metal
15) What is the order of the elements from smallest to largest atomic radius?
Element 1, Element 2, Element 3
Element 1, Element 3, Element 2
Element 2, Element 1, Element 3
Element 2, Element 3, Element 1
16) Which three elements are arranged according to increasing electronegativity values?
N, C, B
N, P, As
N, O, F
F, O, N
17) Which group of elements is arranged in order of increasing atomic radii?
O, S, Se, Te
Fe, Ni, Ag, Au
Rb, K, Na, Li
Y, Zr, Nb, Mo
18) Which statement describes equilibrium between liquid water and water vapor?
The rate of vaporization equals the rate of condensation.
The rate of vaporization is greater than the rate of condensation.
The rate of vaporization equals the rate of sublimation.
The rate of vaporization is greater than the rate of sublimation.
19) Which choice describes the state of the substance at X?
A boiling liquid is in equilibrium with its vapor.
A subliming solid is in equilibrium with its vapor.
A freezing liquid is in equilibrium with its solid.
A melting solid is in equilibrium with its liquid.
20) A sample of metal has a mass of 5.2 g and absorbs 20.0 J of energy as it is heated from 30.0°C to 40.0°C. What is the identity of the metal?
iron
gold
copper
magnesium
21) A 2.0-liter closed container holds 1.0 mole of an ideal gas at a certain temperature and pressure. Which closed container will hold 3.0 moles of this ideal gas at the same temperature and pressure?
a 3.0-liter container
a 6.0-liter container
a 9.0-liter container
a 12.0-liter container
22) What is the condition of the sample at point X?
The sample is in a gaseous state.
The sample is in a liquid state.
The sample is at its critical point.
The sample is at its triple point.
23) What is the approximate temperature of 1.4 moles of a gas with a pressure of 3.25 atmospheres in a 4.738-liter container?
180 K
170 K
150 K
130 K
24) Which choice would be changed by the addition of a catalyst to the reaction?
R
S
T
U
25) A student conducts the following demonstration:
• A 15-g sample of NaHCO3 is placed in a test tube.
• The bottom of the test tube is heated with an open flame.
• Condensation forms on the inside walls of the test tube.
• A burning splint is extinguished when placed at the mouth of the test tube.
What can the student conclude after conducting this demonstration?
The burning splint was extinguished because of a lack of CO2 in the
test tube.
The burning splint was extinguished because of a lack of H2O vapor.
Decomposition produced CO2 and H2O.
Combustion produced O2 and H2O.
26) A chemical equation is shown below.
CaSO4 + AlBr3 → CaBr2 + Al2(SO4)3
What will be the coefficient of CaBr2 when the equation is balanced using the smallest possible whole-number coefficients?
2
3
4
5
27) The equation below represents a chemical reaction.
Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g)
A 5.00-g sample of zinc is added to hydrochloric acid. The amount of hydrochloric acid is sufficient to allow the zinc to react completely. What mass of hydrogen gas does this reaction produce?
0.0308 g
0.0771 g
0.121 g
0.154 g
28) What is the molecular formula of a compound with the empirical formula CH2O and a molecular mass of 60 g/mol?
CH2O
C2H4O2
C2H4O4
C2H2O2
29) What can the student conclude about the experiment?
A chemical reaction occurred because new atoms were created.
A chemical reaction occurred because a new substance was formed.
The popping sound provided evidence that the acid changed physical states.
The popping sound provided evidence that the magnesium atoms were
destroyed.
30) How many O2 particles are in 2.50 moles of O2 at Standard Temperature and Pressure (STP)?
4.15 × 1022 particles
2.41 × 1023 particles
5.02 × 1023 particles
1.51 × 1024 particles
31) Why does an increase in temperature usually increase the rate of a chemical reaction?
because the activation energy of the reaction increases
because the surface area of reacting particles increases
because the proper orientation of reacting particles improves
because the number of effective collisions between reacting particles increases
32) Which action will cause the reaction to shift to the left?
heating the flask with a hot plate
placing the flask in an ice bath
removing H2O from the flask
adding CO to the flask
33) Which temperature has the greatest concentration of product Z?
200 K
300 K
400 K
500 K
34) How would the conditions of equilibrium be affected by decreasing the concentration of substance W?
Substances X and Y would react to replace substance W, and the position of equilibrium would shift to the right.
Substances Y and Z would react to replace substance W, and the position of equilibrium would shift to the left.
This would increase pressure, causing only substance Y to replace substance W and shifting the equilibrium to the right.
This would decrease temperature, causing only substance Z to replace substance W and shifting the equilibrium to the left.
35) A solution has a pOH of 12. Which best describes the solution?
It has a pH of 2 and is a base.
It has a pH of 12 and is a base.
It has a pH of 2 and is an acid.
It has a pH of 12 and is an acid.
36) A student describes a liquid as feeling slippery. The student places red litmus paper into the liquid, and the paper turns blue. What can the student conclude from these observations?
The substance is likely a nonmetal.
The substance is likely a metal.
The substance is likely a base.
The substance is likely an acid.
37) In the titration, 15.0 mL of CsOH solution is neutralized by 38.2 mL of 0.250 M HBr solution. What is the molarity of the CsOH solution?
0.0982 M
0.637 M
1.36 M
10.2 M
38) What type of solution is formed when solid sodium hydroxide (NaOH) is dissolved in water?
an electrolytic solution, because NaOH will dissociate into ions
an electrolytic solution, because NaOH will not dissociate into ions
a nonelectrolytic solution, because NaOH will dissociate into ions
a nonelectrolytic solution, because NaOH will not dissociate into ions
39) A student dissolves 300 g of sugar in 100 g of water at 80°C. The solution is then allowed to cool to 40°C. The appearance of the solution does not change during the cooling. Which term accurately describes the solution at 40°C?
suspension
colloid
supersaturated
unsaturated
40) Which statement explains what happens when potassium chloride (KCl) dissolves in water?
Water molecules surround the potassium chloride but do not exert forces of attraction strong enough to break any bonds.
Water molecules exert forces of attraction that break the potassium chloride apart into potassium ions and chloride ions.
Water molecules exert forces of attraction that break the potassium chloride apart into neutral atoms of potassium and neutral atoms of chlorine.
Water molecules exert forces of attraction that break the potassium chloride apart into potassium atoms and diatomic chlorine gas.
