Unit Test — Unit test Answers
25 verified answers2 views
21
Free Preview
Which is the most important factor in determining the state of a substance?
A
the size of the atoms in a substanceB
the number of molecules in a substanceC
the position of the electrons on the outer valence shellsD
the balance between intermolecular forces and kinetic energy22
Free Preview
Which direction does thermal energy flow in the following diagram?
A
Heat flows from the ice cream to the hand.B
Heat flows from the hand to the ice cream.C
The system is in a state of equilibrium.D
The system is too cold for heat to move.23
Which statement about enthalpy is true?
A
The enthalpy of formation for a pure element in its standard state is always positive.B
The enthalpy of formation for a pure element in its standard state is always negative.C
Enthalpy is a state function because its change depends only on initial and final conditions.D
Enthalpy is not a state function because its change depends on the identities of the reactants and products.24
Consider the following intermediate chemical equations. The overall chemical equation is . To calculate the final enthalpy of the overall chemical equation, which step must occur?
A
Reverse the first equation, and change the sign of the enthalpy. Then, add.B
Reverse the second equation, and change the sign of the enthalpy. Then, add.C
Multiply the first equation by three, and triple the enthalpy. Then, add.D
Divide the third equation by two, and double the enthalpy. Then, add.25
Which graph represents an exothermic reaction?
A
A graph has Reaction progression on the horizontal axis and energy on the vertical axis. A line starts about halfway up the vertical axis and travels a short distance parallel to the horizontal axis; this segment is A plus B. The line then curves up sharply, peaks, and falls sharply to run parallel to and near the horizontal axis; the final segment is C. A double-headed arrow extends from A plus B to C.
B
A graph has Reaction progression on the horizontal axis and energy on the vertical axis. A line segment labeled A plus B starts low and runs parallel to the horizontal axis. The line then curves up sharply, peaks, and falls a short distance to run parallel to the horizontal axis; the final segment is labeled C. A double-headed arrow extends from A plus B to C.
C
A graph has Reaction progression on the horizontal axis and energy on the vertical axis. A line segment labeled A plus B starts halfway up the vertical axis and runs parallel to the horizontal axis for a short distance. The line then peaks and returns to the same level as A plus B and continues parallel to the horizontal axis; this segment is labeled C.
D
A graph has Reaction progression on the horizontal axis and energy on the vertical axis. A line segment labeled A plus B starts low on the vertical axis and runs parallel to the horizontal axis for a short distance. The line then rises sharply and levels off; this level section is labeled C. A double-headed arrow extends from the level of A plus B to that of C.
Did you find these answers helpful?
Verified answers available
TRY EDGENUITY HACKS
- Auto Complete Exams
- Auto Complete Assignments
- Skip Videos Instantly
50,000+ students using this