Metric Conversions and Significant Figures
How many milligrams (mg) are in 2.4 kilograms (kg)?
A. 2,400 mg
B. 24,000 mg
C. 240,000 mg
D. 2,400,000 mg
What is D?
What is the percent by mass of oxygen (O) in dinitrogen tetroxide (N₂O₄)?
A. 36.8%
B. 53.3%
C. 69.6%
D. 80.0%
C. 69.6%
Neon is known to contain three isotopes. Calculate the average atomic mass given the following masses and percent abundances:
Neon-20 (19.99 amu; 90.48%)
Neon-21 (20.99 amu; 0.27%)
Neon-22 (21.99 amu; 9.25%)
a. 20.12 amu
b. 20.18 amu
c. 22.22 amu
d. 22.18 amu
b. 20.18 amu
Select the correct electron configuration for selenium, atomic number 34.
a. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁴
b. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p²
c. 1s²2s²2p⁶3s²3p⁶4s²4p⁶
d. 1s²2s²2p⁶3s²3p⁴3d¹⁰4s²
a. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁴
How many molecules are there in 3.0 moles of ammonia (NH₃)?
a. 6.02 × 10²³ molecules
b. 1.81 × 10²⁴ molecules
c. 9.03 × 10²² molecules
d. 5.00 × 10⁻²⁴ molecules
b. 1.81 × 10²⁴ molecules
Convert 75 millimeters (mm) to centimeters (cm).
A. 0.75 cm
B. 7.5 cm
C. 75 cm
D. 750 cm
B. 7.5 cm
1. What is the percent composition by mass in sulfur trioxide (SO₃)?
A. 25.0% Sulfur and 75.0% Oxygen
B. 40.0% Sulfur and 60.0% Oxygen
C. 50.0% Sulfur and 50.0% Oxygen
D. 60.0% Sulfur and 40.0% Oxygen
B. 40.0% Sulfur and 60.0% Oxygen
Chlorine-37 has 17 protons and 17 electrons. How many neutrons does it have?
a. 17
b. 18
c. 19
d. 20
b. 18
Select the correct noble gas electron configuration for bromine (Br), atomic number 35:
a. [Ar] 4s²3d¹⁰4p⁵
b. [Kr] 4s²3d¹⁰4p⁵
c. [Ne] 3s²3p⁵
d. [Xe] 5s²4d¹⁰5p⁵
a. [Ar] 4s²3d¹⁰4p⁵
How many grams are there in 10 moles of carbon dioxide (CO₂)?
a. 44 g CO₂
b. 220 g CO₂
c. 440 g CO₂
d. 2.65 × 10²⁵ g CO₂
c. 440 g CO₂
How many deciliters (dL) are in 6 liters (L)?
A. 0.6 dL
B. 6 dL
C. 60 dL
D. 600 dL
C. 60 dL
Determine the molar mass of aluminum sulfate: Al₂(SO₄)₃
A. 342.2 g/mol
B. 310.1 g/mol
C. 298.1 g/mol
D. 420.4 g/mol
A. 342.2 g/mol ✅
Three different isotopes of the same element have
A. same number of protons
B. same mass number
C. same number of neutrons
D. same atomic mass
A. same number of protons
The statement that electrons occupy orbitals singly before pairing is:
a. The Aufbau Principle
b. Bohr’s Law
c. Hund’s Rule
d. The Pauli Exclusion Principle
c. Hund’s Rule
How many moles of calcium (Ca) are equivalent to 3.01 × 10²³ atoms?
a. 5.00 × 10⁴⁶
b. 0.50
c. 6.02 × 10²³
d. 1.81 × 10²⁴
b. 0.50
How many significant figures are present in the value 4050?
A. 2
B. 3
C. 4
D. 5
B. 3
A compound has an empirical formula of CH2 and a molar mass of 42.08 g/mol. What is its molecular formula?
a. CH2
b. C2H4
c. C3H4
d. C3H6
d. C3H6
Which statement is not correct?
A. Mass Number = Number of protons + number of neutrons
B. Atomic Number = Number of protons
C. Number of protons = number of electrons in an electrically neutral atom
D. Mass Number = Atomic Number
D. Mass Number = Atomic Number
The statement that no two electrons in an orbital of an atom can have the same spin
a. Hund’s Rule
b. The Aufbau Principle
c. Bohr’s Law
d. The Pauli Exclusion Principle
d. The Pauli Exclusion Principle
Copper has a density of 8.96 g/cm³. What would be the mass of a copper sample that occupies a volume of 2.00 cm³?
a. 17.9 g
b. 10.2 g
c. 1.78 g
d. 0.224 g
a. 17.9 g
How many significant figures are present in the value 0.006020?
A. 2
B. 3
C. 4
D. 5
C. 4
A compound has a percent composition by mass of 40.00% C, 6.71% H, and 53.29% O. Determine the empirical formula.
a. CHO
b. C2H2O2
c. C3H3O
d. CH2O
d. CH2O
A sulfur isotope consists of 16 protons, 16 electrons, and 18 neutrons. Its mass number is:
a. 16
b. 18
c. 32
d. 34
c. 32
The statement that an electron occupies the lowest available energy level orbital first is:
a. Hund’s Rule
b. The Aufbau Principle
c. Bohr’s Law
d. The Pauli Exclusion Principle
b. The Aufbau Principle
79. A solid iron block has a mass of 63.0 g and a volume of 8.00 cm³. Find the density of iron.
a. 7.88 g/cm³
b. 6.75 g/cm³
c. 8.50 g/cm³
d. 7.50 g/cm³
a. 7.88 g/cm³