Exam 2 Review Questions Flashcards
The first law of thermodynamics
A. Poses that energy is neither created nor destroyed during a change in a system
b. cannot be used to predict the direction of a reaction.
c. applies to all defined systems in the universe.
D. A, b, and c are correct
D
Entropy is conveniently defined as
a. the amount of kinetic energy that can be utilized by a system
b. the amount of work done on a system by the surroundings.
c. the amount of randomness or freedom each component has in a system.
d. the way a system responds when heat flows out of it to the surroundings.
C
In a power plant, the kinetic energy in the steam is directly converted to
A. Electrical energy in the generator
B. Mechanical energy in the turbine
C. Potential energy in the turbine
D. Kinetic energy in the water
B
- A power plant cannot convert 100% of the energy stored in the fuel to electricity because
a. energy conversions include some loss of heat to the surroundings because compartments cannot be completely insulated.
b. conversion of potential energy to mechanical energy results in loss of entropy.
c. a and b are both incorrect.
d. a and b are both correct.
D
- The combustion of methane gas is given by
CH4 (g) + 2O2 (g) ® CO2(g) + 2H2O(g)
Much heat is given off during this reaction. The reaction is
a. exothermic.
b. endothermic.
c. neither.
d. it cannot be determined.
A
. The reaction in question 5 requires breaking the bonds that hold one mole of methane. The amount of energy required to do so is
a. 416 kJ.
b. 832 kJ.
c. 1,248 kJ.
d. 1,664 kJ.
D
- The reaction in question 5 yields one mole of carbon dioxide. The amount of energy that is given off by the formation of the bonds in one mole of CO2 is
a. 803 kJ.
b. 1,606 kJ.
c. 2,409 kJ.
d. 3,212 kJ.
B
- As molecules undergo changes during a reaction, bonds between atoms in reactant molecules must be broken in order to allow the atoms to rearrange into product molecules. The process of breaking bonds in the reactants is
a. exothermic
b. endothermic
c. isothermic.
d. a, b, and c are correct.
B
- During distillation, heat is applied to a sample and the vapors ascend up a column. Short hydrocarbon will condense (go from the gas to the liquid phase)
a. at the top of the column because the short molecules remain in the gas phase at the hot temperature near the bottom of the column, but condense at the cooler temperatures near the top.
b. at the middle of the column because the steam interferes with the attractive forces between molecules.
c. at the bottom of the column because that is where the attractive forces between molecules are greatest.
d. at the bottom of the column because the attractive forces between molecules increase as the molecules become shorter.
A
- Fuel cracking is
a. a process used to create diesel from tar.
b. a process used to increase the price of gasoline.
c. a process used to generate diesel from food industry waste.
d. a process used to generate gasoline from diesel.
D
- A polar bond is shown in
C-O (I) C=O (II) H-H (III)
a. I and II
b. I and III
c. I, II, and III
d. II and III
A
- The bond polarity of N-H, in comparison to that of C-H, is
a. greater.
b. identical.
c. lower
d. alwayS CHANGING
A
- Water has a
a. lower boiling point than predicted by its molar mass due to the covalent O-H bonds.
b. higher boiling point than predicted by its molar mass due to the covalent O-H bonds.
c. lower boiling point than predicted by its molar mass due to hydrogen bonds.
d. higher boiling point than predicted by its molar mass due to hydrogen bonds.
D
- Water that has been cooled to 0-4°C
a. has more covalent bonds than 5-20°C water, making it less dense.
b. is denser than 5-20°C water, therefore it floats to the top of the warmer water below it.
c. has fewer hydrogen bonds than 5-20°C water, and this affects the density.
d. is less dense than 5-20°C water, therefore it floats on top of the warmer water below it.
D
