WorksheetsPI B
Total questions: 14
Worksheet time: 21mins
The enthalpy of fusion of methanol (CH3OH) is 3.16 kJ/mol. How much heat would be absorbed or released upon freezing 25.6 grams of methanol?
2.52 kJ absorbed
0.253 kJ absorbed
2.52 kJ released
3.95 kJ released
3.95 kJ absorbed
A student runs a reaction in a closed system. In the course of the reaction, 64.7 kJ of heat is released to the surroundings and 14.3 kJ of work is done on the system. What is the change in internal energy (∆U) of the reaction?
-79.0 kJ
50.4 kJ
79.0 kJ
-50.4 kJ
90.4kJ
Consider the plot below for three different samples of pure water. Based on the plot, which answer choice below is a correct statement regarding the three samples of pure water?
All three samples have the same heat capacity.
Sample Z has the greatest heat capacity.
Sample X has the smallest mass.
All three samples have different specific heat capacities.
Sample Y would require the least heat to raise its temperature by 1 K.
A CD player and its battery together do 500 kJ of work, and the battery also releases 250 kJ of energy as heat and the CD player releases 50 kJ as heat due to friction from spinning. What is the change in internal energy of the system, with the system regarded as the battery and CD player together?
+200 kJ
-700 kJ
-750 kJ
-200 kJ
-800 kJ
Which of the following is/are a reason that water is a desirable heat sink for use in calorimeters?
I) Water’s heat specific capacity is very precisely known.
II) Water is readily available.
III) Water has an unusually large specific heat capacity.
I only
II and III
I and II
I, II and III
II only
Consider a thermodynamic system that is simultaneously releasing heat and doing work. The internal energy of this system will:
Decrease
Increase, decrease, or stay the same depending on the magnitudes of heat and work
Stay exactly the same.
Increase
The formation of chemical bonds from separated atoms
is never spontaneous.
increases entropy.
may be either endothermic or exothermic.
is always exothermic.
is always endothermic.
Which of O2(g), O2(l), H2(g), H2(l), H2O(g), H2O(l) have a standard enthalpy of formation equal to zero?
O2(g), O2(l), H2(g), H2(l), H2O(g), H2O(l)
O2(g), H2(g), H2O(g)
O2(g), O2(l), H2(g), H2(l)
O2(g), H2(g)
All of them, but only at absolute zero.
Calculate the heat of formation for 2.6 mol of sulfur dioxide (SO2) from its elements, sulfur and oxygen. Use the balanced chemical equation and the following information.
S(s) + 1.5 O2(g) → SO3(g) ∆H0 = −395.2 kJ/mol
2SO2(g) + O2(g) → 2SO3(g) ∆H0 = −198.2 kJ/mol
-414.54
-562.59
-384.93
-769.86
-592.2
Answer the question below:
Specific; gram; extensive
Molar; gram; intensive
Specific; mole; extensive
Molar; gram; extensive
Specific; gram; intensive
Consider the combustion reaction below.
2 CH3OH(g) + 3 O2(g) → 2 CO2(g) + 4 H2O(ℓ)
If this reaction took place in a closed, rigid container, work would be (positive/negative/zero) and heat would be (positive/negative/zero).
positive, zero
positive, negative
zero, negative
zero, positive
negative, positive
A system did 150 kJ of work and its internal energy increased by 60 kJ. How much energy did the system gain or lose as heat?
The system gained 210 kJ of energy as heat.
The system lost 90 kJ of energy as heat.
The system lost 210 kJ of energy as heat.
The system gained 90 kJ of energy as heat.
The system gained 60 kJ of energy as heat.
Calculate the standard reaction enthalpy for the reaction:
730 kJ · mol−1
−846 kJ · mol−1
−1,418 kJ · mol−1
336 kJ · mol−1
−452 kJ · mol−1
Which statement about internal energy is true?
The internal energy of a system is equal to w at constant volume.
The internal energy of a system is equal to q at constant volume.
The internal energy of a system is constant at constant volume.
The internal energy of a system is equal to w at constant pressure.
The internal energy of a system is constant at constant pressure.
