Question

A sample of a compound ________ A. breaks into its constituent atoms during phase changes. B. is a homogeneous mixture. C. contains atoms that can be physically separated from each other. D. contains at least two types of atoms in a constant, fixed ratio. E. has a variable composition depending on its temperature. 2. Which pair of atoms constitutes a pair of isotopes of the same element? A. X X B. X X C. X X D. X X E. X X 3. Which of the following statements is FALSE? A. The identity of an atom can be determined solely by its atomic number. B. The identity of an isotope can be determined solely by its mass number. C. Atoms of different elements may have the same mass numbers. D. Atoms of different elements cannot contain the same number of protons. E. The different isotopes of an element are not always equally abundant. 4. Which of the following elements would you expect to have the greatest first ionization energy? A. Br B. Ga C. Ge D. K E. Se 5.When are an empirical formula and a molecular formula the same? A. always B. when the mass of the empirical formula unit is equal to the molecular mass C. when the mass percentages of all of the elements in the two formulas are the same D. never E. when the molecular mass is an integer multiple of formula unit mass 6. Nitrite (NO2-) is an important nutrient in the eutrophic zone of the ocean. Which set of resonance structures below best describes the bonding in this ion? A. a B. b C. c D. d E. none of these

A sample of a compound ________
A. breaks
into its constituent atoms during phase changes.
B. is
a homogeneous mixture.
C. contains
atoms that can be physically separated from each other.
D. contains
at least two types of atoms in a constant, fixed ratio.
E. has
a variable composition depending on its temperature.
2. Which pair of atoms constitutes a pair of isotopes of
the same element?
A. X X B. X X
C. X X D. X X
E. X X
3. Which of the following statements is FALSE?
A. The
identity of an atom can be determined solely by its atomic
number.
B. The
identity of an isotope can be determined solely by its mass
number.
C. Atoms
of different elements may have the same mass numbers.
D. Atoms
of different elements cannot contain the same number of
protons.
E. The
different isotopes of an element are not always equally
abundant.
4.
Which of the following elements would
you expect to have the greatest first ionization energy?
A. Br B. Ga C. Ge
D. K E. Se
5.When are an empirical formula and a molecular formula the
same?
A. always
B. when
the mass of the empirical formula unit is equal to the molecular
mass
C. when
the mass percentages of all of the elements in the two formulas are
the same
D. never
E. when
the molecular mass is an integer multiple of formula unit mass
6. Nitrite (NO2-) is an important
nutrient in the eutrophic zone of the ocean. Which set of resonance
structures below best describes the bonding in this ion?

A. a B. b C. c
D. d E. none
of these

Added by Lu-S K.

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