Scientific Method
All of the following are steps in the scientific method except
a. observing and recording data.
b. forming a hypothesis.
c. discarding data inconsistent with the hypothesis.
d. making predictions based on a theory.
c. discarding data inconsistent with the hypothesis
The number of significant figures in the measurement 0.000 305 kg is
a. two.
b. three.
c. six.
d. seven.
b. three.
Except for in the simplest type of hydrogen atom, all nuclei consist of
a. protons and electrons.
b. protons and neutrons.
c. neutrons and positrons.
d. electrons and positrons.
b. protons and neutrons.
What is the definition of one atomic mass unit?
a. 1 g of any element
b. 1 mol of any element
c. 1/12 of the mass of a carbon-12 atom
d. 1/12 of the mass of any atom
c. 1/12 of the mass of a carbon-12 atom
How many different orientations are there for d orbitals?
a. 1
b. 3
c. 5
d. 7
c. 5
A proposed explanation that is based on observations and that can be tested is known as a(n)
a. principle.
b. experiment.
c. law.
d. hypothesis.
Hypothesis
The measurement 0.0255 g, rounded off to two significant figures, would be
a. 0.02 g.
b. 0.025 g.
c. 0.026 g.
d. 2.5 x 102 g.
c. 0.026 g.
Rutherford called the region that deflected alpha particles
a. an electron.
b. a positron.
c. a nucleus.
d. a quark.
c. a nucleus.
In a ground-state hydrogen atom in which orbital is the electron?
a. 1s
b. 2s
c. 2p
d. 3s
a. 1s
What is the maximum number of electrons that a single orbital can hold?
a. 1
b. 2
c. 3
d. 4
b. 2
A theory is likely to be revised as the explanation of an observed phenomenon when
a. one study contradicts the theory.
b. repeated observations conflict with the theory.
c. a new method is used to gather data.
d. a leading scientist feels that it is invalid.
b. repeated observations conflict with the theory.
Written in scientific notation, the measurement 0.000 065 cm is
a. 65 x 10-4 cm.
b. 6.5 x 10-5 cm.
c. 6.5 x 10-6 cm.
d. 6.5 x 10-4 cm.
b. 6.5 x 10-5 cm.
The atomic number of an element is
a. the number of protons in each atom of the element.
b. 1 mol of the element.
c. the mass of the element.
d. the number of neutrons in each atom of the element.
a. the number of protons in each atom of the element.
The molar mass of an element is numerically equal to the element’s
a. average number of electrons.
b. average number of protons.
c. average atomic number.
d. average atomic mass.
d. average atomic mass.
According to the Aufbau principle, which of the following sublevels is lowest in energy?
a. 3d
b. 4s
c. 4p
d. 5s
b. 4s
Ten plants are grown in equal amounts of sunlight with equal amounts of water and varying amounts of fertilizer. Sunlight and water are
a. variables.
b. experiments.
c. systems.
d. controls.
d. controls.
What is the sum of 100.0 g and 0.01 g, expressed in scientific notation and written with the correct number of significant figures?
a. 10 001 x 10-2 g
b. 1.0 x 102 g
c. 1.000 x 102 g
d. 1.00 x 102 g
c. 1.000 x 102 g
Isotopes are atoms of the same element that have different
a. masses.
b. charges.
c. numbers of electrons.
d. atomic numbers.
a. masses.
How many electrons are present in an atom of calcium that has the electron configuration 1s22s22p63s23p64s2?
a. 20
b. 16
c. 6
d. 36
20
The ground-state electron configuration of neon is 1s22s22p6. In this arrangement, how many of neon’s p orbitals are completely filled?
a. 1
b. 2
c. 6
d. 3
3
Which of these observations is qualitative rather than quantitative?
a. A chemical reaction is complete in 2.3 s.
b. The solid has a mass of 23.4 g.
c. The density of aluminum is 2.70 g/cm3.
d. Salt deposits form from an evaporated liquid.
d. Salt deposits form from an evaporated liquid.
For numbers less than 0.1, such as 0.06, the zeros to the right of the decimal point but before the first nonzero digit
a. are significant.
b. show the decimal place of the first digit.
c. show that the zero on the left side of the decimal is not significant.
d. are always uncertain.
b. show the decimal place of the first digit.
The nuclear symbol for uranium-235 should be written as
235/92 U
The noble-gas notation for the electron configuration of bromine is [Ar] 3d104s24p5. How many unpaired electrons are there in an atom of bromine in the ground state?
a. 0
b. 1
c. 3
d. 5
1
How many moles of atoms are in 50.15 g of mercury (atomic mass 200.59 amu)?
50.15 g Hg * ( 1 mol Hg/ 200.59 g Hg) = 0.2500 mol Hg