CHEM 115 END OF COURSE EXAM 2026/2027 QUESTIONS
AND SOLUTIONS RATED A+
✔✔Draw skeletal molecular structure of C3H8 - ✔✔(its the structure drawn without the
hydrogen atoms)
✔✔A gallium-69 ion (69Ga2+) contains when the atomic number is 31
(a) 69 protons, 31 neutrons and 33 electrons.
(b) 31 protons, 38 neutrons and 29 electrons.
(c) 31 protons, 69 neutrons and 29 electrons.
(d) 69 protons, 31 neutrons and 29 electrons.
(e) 31 protons, 38 neutrons and 33 electrons. - ✔✔(b) 31 protons, 38 neutrons and 29
electrons.
✔✔when drawing the skeletal molecular structure do you have to include nonbonding
electrons if there are any?
for example, draw C6H14O - ✔✔YES
✔✔Exothermic reactions are defined by a _____.
Please choose the correct answer from the following choices, and then select the
submit answer button.
a) negative ΔU∘
b) negative ΔH∘
c) positive ΔH∘
d) positive ΔU∘ - ✔✔negative ΔH∘
because they release energy to their surroundings
✔✔shape of [NO2]+ - ✔✔linear
about 180
✔✔A calorimetry experiment is performed where a piece of copper at 87.2 °C is placed
inside a calorimeter that contains water at 1.3 °C. Which statement correctly describes
the relationship between q copper and q water?
q copper= 1q/water
q copper= q water
−q copper= q water
, q copper= −q water - ✔✔q copper= q water
✔✔shape of [NO2]- - ✔✔bent
120
✔✔If equal masses of each substance absorb the same amount of heat, which
substance undergoes the greatest temperature change?
a) highest J/g(c)
b) lowest J/g(c) - ✔✔b) lowest J/g(c)
✔✔Shape [NO3]- - ✔✔trigonal planar
120
✔✔What bond angle is associated with a set of sp2 hybrid orbitals? - ✔✔120
✔✔what is delta H and delta U - ✔✔Delta H is the change in enthalpy which is equal to
Delta U+P(Delta V)
delta U is the change in internal energy of the system. q is the heat of the system
✔✔What bond angle is associated with a set of sp3 hybrid orbitals? - ✔✔109.5
✔✔write the isotope symbol for cobalt-60 when its atomic number is always 27 -
✔✔60/27 Co
✔✔What bond angle is associated with a set of sp hybrid orbitals? - ✔✔180
✔✔which type of radiation has a negative charge - ✔✔beta
✔✔write the condensed structural formula for Propane (C3H8) - ✔✔CH3 CH2 CH3
✔✔which type of radiation is pure energy - ✔✔Gamma
✔✔what type of radiation has the most massive particles - ✔✔alpha
✔✔what is a condensed formula - ✔✔It reflects the order that the molecules are
attached
✔✔What is a molecular formula? - ✔✔A molecular formula is the actual number of
atoms of each element in a molecule
AND SOLUTIONS RATED A+
✔✔Draw skeletal molecular structure of C3H8 - ✔✔(its the structure drawn without the
hydrogen atoms)
✔✔A gallium-69 ion (69Ga2+) contains when the atomic number is 31
(a) 69 protons, 31 neutrons and 33 electrons.
(b) 31 protons, 38 neutrons and 29 electrons.
(c) 31 protons, 69 neutrons and 29 electrons.
(d) 69 protons, 31 neutrons and 29 electrons.
(e) 31 protons, 38 neutrons and 33 electrons. - ✔✔(b) 31 protons, 38 neutrons and 29
electrons.
✔✔when drawing the skeletal molecular structure do you have to include nonbonding
electrons if there are any?
for example, draw C6H14O - ✔✔YES
✔✔Exothermic reactions are defined by a _____.
Please choose the correct answer from the following choices, and then select the
submit answer button.
a) negative ΔU∘
b) negative ΔH∘
c) positive ΔH∘
d) positive ΔU∘ - ✔✔negative ΔH∘
because they release energy to their surroundings
✔✔shape of [NO2]+ - ✔✔linear
about 180
✔✔A calorimetry experiment is performed where a piece of copper at 87.2 °C is placed
inside a calorimeter that contains water at 1.3 °C. Which statement correctly describes
the relationship between q copper and q water?
q copper= 1q/water
q copper= q water
−q copper= q water
, q copper= −q water - ✔✔q copper= q water
✔✔shape of [NO2]- - ✔✔bent
120
✔✔If equal masses of each substance absorb the same amount of heat, which
substance undergoes the greatest temperature change?
a) highest J/g(c)
b) lowest J/g(c) - ✔✔b) lowest J/g(c)
✔✔Shape [NO3]- - ✔✔trigonal planar
120
✔✔What bond angle is associated with a set of sp2 hybrid orbitals? - ✔✔120
✔✔what is delta H and delta U - ✔✔Delta H is the change in enthalpy which is equal to
Delta U+P(Delta V)
delta U is the change in internal energy of the system. q is the heat of the system
✔✔What bond angle is associated with a set of sp3 hybrid orbitals? - ✔✔109.5
✔✔write the isotope symbol for cobalt-60 when its atomic number is always 27 -
✔✔60/27 Co
✔✔What bond angle is associated with a set of sp hybrid orbitals? - ✔✔180
✔✔which type of radiation has a negative charge - ✔✔beta
✔✔write the condensed structural formula for Propane (C3H8) - ✔✔CH3 CH2 CH3
✔✔which type of radiation is pure energy - ✔✔Gamma
✔✔what type of radiation has the most massive particles - ✔✔alpha
✔✔what is a condensed formula - ✔✔It reflects the order that the molecules are
attached
✔✔What is a molecular formula? - ✔✔A molecular formula is the actual number of
atoms of each element in a molecule
