Enthalpy of Reaction Answers

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Consider the following enthalpy diagram and enthalpies of intermediate and overall chemical reactions.Which of the following statements is true?

Question illustration
A
The overall chemical reaction is exothermic.
B
There are two intermediate reactions in this system.
C
The third intermediate reaction is endothermic.
D
The longest arrow represents the overall chemical reaction.
3

Consider the following intermediate chemical equations.Which overall chemical equation is obtained by combining these intermediate equations?

Question illustration
A
Upper C upper H subscript 4 plus 2 upper O subscript 2 (g) right arrow upper C upper O subscript 2 (g) plus 2 upper H subscript 2 upper O (l).
Option A
B
Upper C upper H subscript 4 plus 2 upper O subscript 2 (g) right arrow upper C upper O subscript 2 (g) plus 2 upper H subscript 2 upper O (g).
Option B
C
Upper C upper H subscript 4 plus 2 upper O subscript 2 (g) right arrow upper C upper O subscript 2 (g) plus 4 upper H subscript 2 upper O (g) plus 2 upper H subscript 2 upper O (l).
Option C
D
Upper C upper H subscript 4 plus 2 upper O subscript 2 (g) right arrow upper C upper O subscript 2 (g) plus 6 upper H subscript 2 upper O (g).
Option D
5

What is enthalpy?

A
the total concentration of the system
B
the total heat content of the system
C
the total pressure of the system
D
the total disorder of the system
7

Consider the following intermediate chemical equations.In the final chemical equation, HF and O are the products that are formed through the reaction between and F. Before you can add these intermediate chemical equations, you need to alter them by multiplying the

Question illustration
A
second equation by 2 and reversing the first equation.
B
first equation by 2 and reversing it.
C
first equation by (1/2) and reversing the second equation.
D
second equation by 2 and reversing it.
9

How should the enthalpy of an intermediate step be manipulated when used to produce an overall chemical equation?

A
Multiply the enthalpy by 1 if the chemical equation is reversed.
B
Multiply the enthalpy by –1 if the chemical equation is reversed.
C
Add 2 to the enthalpy if the coefficients must be doubled.
D
Add 2 to the enthalpy if the coefficients must be cut in half.
10

If a chemical reaction is reversed, what happens to the enthalpy of the reaction?

A
The enthalpy of the reaction becomes zero.
B
The enthalpy of the reaction doubles.
C
The sign of the enthalpy of the reaction reverses.
D
The enthalpy of the reaction is halved.

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