Unit 1 Flashcards
An element __________
a.
can be separated into its components by physical methods.
b.
always has the same chemical properties regardless of its source.
c.
cannot be separated into simpler substances by chemical methods.
d.
can also be a compound.
e.
exists only as atoms, not as molecules.
c.
cannot be separated into simpler substances by chemical methods.
Which one of the following represents a chemical change?
a. Mercury (II) oxide is heated to and forms mercury metal and oxygen gas. b. Rubbing alcohol evaporates. c. Iodine vapor deposits on a surface. d. Iron metal is separated from sand using a magnet. e. Rock salt is pulverized.
a.
Mercury (II) oxide is heated to and forms mercury metal and oxygen gas.
Equal amounts of water are present under the following conditions. In which case do the water molecules have the highest kinetic energy?
a. as ice at 10°C (14°F) d. in the gas phase at 150°C (302°F) b. as steam at 100°C (212°F) e. in the solid phase at 0°C (32°F) c. in the liquid phase at 80°C (176°F)
d.
in the gas phase at 150°C (302°F)
Which of the following represents the largest mass?
a. 250 ng d. 0.25 kg b. 25 μg e. 25 mg c. 2.5 g
d.
0.25 kg
- A student conducts repeated trials to determine the density of a sample of seawater and obtains the following results: 1.321 g/mL; 1.323 g/mL; 1.319 g/mL; and 1.321 g/mL. Known values are reported to be in the 1.02 to 1.09 g/mL range. The experimental results are __________
a. less precise than the known values. d. precise and accurate. b. more accurate than the known values. e. inaccurate but precise. c. imprecise but accurate.
e.
inaccurate but precise.
According to the law of definite proportions, __________
a.
atoms forming a given compound react in variable proportions depending on conditions.
b.
different samples of the same compound contain the same proportions of the same elements.
c.
all compounds containing the same types of atoms have identical properties.
d.
all compounds containing the same types of atoms have relative masses that are whole-number multiples.
e.
only one type of molecule can be produced when two elements combine.
b.
different samples of the same compound contain the same proportions of the same elements.
Which of the following statements is NOT true regarding blackbody radiation, the ultraviolet catastrophe, and Planck’s view of electromagnetic radiation?
a.
A blackbody radiator does not absorb and emit one wavelength preferentially over another.
b.
The emission spectrum of a blackbody radiator depends on its temperature.
c.
A blackbody radiator cannot emit an infinite amount of radiation.
d.
Planck theorized that real objects can only absorb or emit discrete packets of electromagnetic radiation.
e.
The ultraviolet catastrophe disappears if emission spectrum of a blackbody radiator is continuous.
e.
The ultraviolet catastrophe disappears if emission spectrum of a blackbody radiator is continuous.
Which of the following statements regarding the Bohr model of the atom is NOT correct?
a.
Changes in the energy of the atom involve the electron transitioning between allowed orbits.
b.
The atom has discrete energy levels described by a quantum number, n.
c.
The electron does not radiate energy and spiral into the nucleus if it is in an allowed orbit.
d.
The atom has zero energy when in its ground state.
e.
The energy of an orbit is inversely proportional to n2.
d.
The atom has zero energy when in its ground state.
Calcium is an example of __________
a. an alkali metal. d. a halogen. b. a transition metal. e. a chalcogen. c. an alkaline earth metal.
c.
an alkaline earth metal.
How many grams of P4 (123.88 g/mol) would contain the same number of atoms as 154 g S8 (256.48 g/mol)?
a. 18.6 g P4 d. 149 g P4 b. 40.2 g P4 e. 596 g P4 c. 124 g P4
d.
149 g P4
Silicon brass contains 82.0% Cu, 14.0% Zn, and 4.00% Si by mass, and its density is 8.28 g/cm3. How many moles of silicon are present in 22.0 cm3 of silicon brass?
a. 6.48 mol Si d. 0.260 mol Si b. 5.32 mol Si e. 0.0946 mol Si c. 0.908 mol Si
d.
0.260 mol Si
Suppose a blue light emitting photons with λ = 470 nm is rated at 60W (60 J of energy are emitted per second). How many photons are emitted in 5.0 seconds?
a. 4.2 x 10^19 photons d. 2.1 × 10^38 photons b. 7.1 x 10^20 photons e. 1.6 x 10^9 photons c. 1.4 x 10^20 photons
b.
7.1 1020 photons
What is the shortest wavelength of light emitted by an excited hydrogen atom when nfinal = 2?
a. 91.16 nm d. 364.6 nm b. 121.5 nm e. 656.3 nm c. 273.5 nm
d.
364.6 nm
Which of the following statements regarding orbitals and wave functions is true?
a.
Wave functions are mathematical solutions to the Schrödinger wave equation.
b.
Wave functions specify where an electron is at any given time.
c.
An orbital encloses a region in space around the nucleus where the probability of finding an electron is 1.
d.
The square of the wave function describes how the electron matter wave varies in time and space.
e.
All sine functions are solutions to the Schrödinger equation for the hydrogen atom.
a.
Wave functions are mathematical solutions to the Schrödinger wave equation.
If the principal quantum number is seven (n = 7) and the angular momentum quantum number is three ( =3), which of the following values is NOT an allowed value of the magnetic quantum number (m)?
a. 0 d. –3 b. 1 e. 4 c. 2
e.
4
Which of the following elements has the ground-state electron configuration 1s^22s^22p^63s^23p^4?
a. Al d. P b. S e. Ar c. Cl
a. Al d. P b. S e. Ar c. Cl
Which of the following species is NOT isoelectronic to the others?
a. Br– d. As3 b. Kr e. Y3+ c. Ca2+
c.
Ca2+
In what ratio will alkaline earth metals pair with halogens when they form ionic compounds?
a. 3:1 d. 1:2 b. 2:1 e. 1:3 c. 1:1
d.
1:2
The first eight successive ionization energies (IE1, IE2, …) for Al are 578, 1817, 2745, 11,577, 14,842, 18,379, 23,326, and 27,465 kJ/mol. What is the probable explanation for the large jump in energy observed between IE3 and IE4?
a.
Zeff decreases as electrons are removed.
b.
Electrons in ns and np orbitals are equal in energy.
c.
IE4 reflects that inner shell electrons with a lower n value are starting to be removed.
d.
Aluminum cannot lose four electrons so IE4 is meaningless.
e.
Electrons with higher angular momentum are harder to remove.
c.
IE4 reflects that inner shell electrons with a lower n value are starting to be removed.
Which of the following has the largest atomic radius?
a. Ba d. Sr b. Hg e. Hf c. Rn
a.
Ba
A 13 g piece of dark chocolate is found to contain 14 mg caffeine, while the caffeine content in a 20-fluid-ounce mug of coffee might be 415 mg. How many pounds of chocolate would you have to eat to consume the amount of caffeine in 2 mugs of this particular coffee? (1 lb = 453.6 g)
1.7 lb
What is the average atomic mass of a sample of highly enriched uranium uranium that contains exactly 20% uranium-235 (235.04 amu) and 80% uranium-238 (238.05 amu)?
ANS: 237.45 amu
If light at 193 nm from an argon–fluoride laser is incident on a gold metal surface, electrons with kinetic energy of 1.80 10–19 J are produced. What is the work function of gold in kJ/mol? What is the minimum wavelength of light in nm required to produce photoelectrons from gold (zero kinetic energy)?
511 kJ/mol; 234 nm
Identify which element, potassium or bromine, has the larger electron affinity and explain why.
Bromine has the larger electron affinity because it is at the end of a row in the periodic table; consequently, it has a large effective nuclear charge and is able to attract an additional electron to produce Br – with the electron configuration of krypton.
