AnswersISP ONLY Chemistry S2 Q3000XXUnit Test

Unit Test — Unit test Answers

12 verified answers
1
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Which energy change takes place when gasoline evaporates from a fuel gas can?

A
Energy is released.
B
Energy is absorbed.
C
Energy remains stationary.
D
Energy becomes transformed.
2
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The molar heat of fusion of gold is 12.550 kJ mol–1. At its melting point, how much mass of melted gold must solidify to release 235.0 kJ of energy?Use .

Question illustration
A
18.73 g
B
222.5 g
C
2,949.3 g
D
3,688.3 g
3

The overall change in enthalpy of a reaction depends only on

A
the reactants and the products.
B
the path that is taken from the reactants to the products.
C
the reactants and the catalysts only.
D
the reactants, the products, and the catalysts.
4

According to Hess’s law, if a series of intermediate reactions are combined, the enthalpy change of the overall reaction is

A
the difference between the enthalpies of the intermediate reactions.
B
the sum of the enthalpy changes of the intermediate reactions.
C
the product of the enthalpy changes of the intermediate reactions.
D
the fraction of the individual enthalpies of the intermediate reactions.
5

According to the enthalpy diagram below, which of the following statements is true?

Question illustration
A
Arrows A and D represent the enthalpy of the intermediate chemical reactions.
B
Arrow C represents the enthalpy of the overall chemical reaction.
C
Arrow C indicates that the third intermediate reaction is exothermic.
D
Arrow B indicates that the second intermediate reaction is exothermic.
6

Which type of reaction is always spontaneous?

A
an exothermic reaction that has an increase in disorder
B
an exothermic reaction that has a decrease in disorder
C
an endothermic reaction that has an increase in disorder
D
an endothermic reaction that has a decrease in disorder
7

The molar heat of fusion for water is 6.01 kJ/mol. How much energy is released when 36.8 g of water freezes at its freezing point?Use .

Question illustration
A
6.12 kJ
B
12.3 kJ
C
108 kJ
D
221 kJ
8

Consider the following intermediate chemical equations.What is the enthalpy of the overall chemical reaction ?

Question illustration
A
-4,580 kJ
B
-1,300 kJ
C
1,300 kJ
D
4,580 kJ
9

What is Gsystem for the system that is described by the following data?Hsystem = –345 kJ, T = 293 K, Ssystem = 465 J/KGsystem = Hsystem – TSsystem

Question illustration
A
–481 kJ
B
–209 kJ
C
413 kJ
D
135,900 kJ
10

What is the definition of entropy?

A
a system that can exchange both matter and energy with its surroundings
B
a measure of the overall disorder of a system
C
a quantity that measures the overall spontaneity of a reaction
D
a process that will proceed without continuous external influence
11

Consider the following equation.Fe2O3(s) + 3H2(g) 2Fe(s) + 3H2O(g)H = 98.8 kJ, and S = 141.5 J/K. Is this reaction spontaneous or nonspontaneous at high and low temperatures?

Question illustration
A
spontaneous at high temperatures, nonspontaneous at low temperatures
B
nonspontaneous at high and low temperatures
C
spontaneous at low temperatures, nonspontaneous at high temperatures
D
spontaneous at high and low temperatures
12

Which energy changes are associated with a liquid freezing?

A
Energy is released as potential energy increases.
B
Energy is absorbed as potential energy increases.
C
Energy is released as potential energy decreases.
D
Energy is absorbed as potential energy decreases.

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