AnswersChemistryEnergy in Chemical Reactions

Practice Test Answers

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An ice cube is dropped into a glass of milk at 20 times degree C Which statement explains the transfer of kinetic energy KE ?

A
Because ice has higher KE than milk, KE is transferred from the molecules of ice to the milk.
B
Because milk has higher KE than ice, KE is transferred from the milk to the molecules of ice.
C
Because ice has higher KE than milk, KE is transferred from the milk to the molecules of ice.
D
Because milk has higher KE than ice, KE is transferred from the molecules of ice to the milk.
2
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Which statement defines specific heat capacity for a given sample?

A
the quantity of heat that is required to raise 1 g of the sample by 1 times degree C (Kelvin) at a constant pressure
B
the quantity of heat that is required to raise the sample’s temperature by 1 times degree C (Kelvin)
C
the temperature that a given sample can withstand
D
the temperature of a given sample
3

A copper rod that has a mass of 200 point 0 g has an initial temperature of 20 point 0 times degree C and is heated to 40 point 0 times degree C If 1 comma 540 cap j of heat are needed to heat the rod, what is the specific heat of copper? Use q is equal to m cap c sub p triangle cap t

A
0 point 0 6 4 9 the fraction with numerator cap j and denominator open paren g times degree cap c close paren
B
0 point 0 1 3 0 the fraction with numerator cap j and denominator open paren g times degree cap c close paren
C
0 point 3 8 5 the fraction with numerator cap j and denominator open paren g times degree cap c close paren
D
0 point 1 9 3 the fraction with numerator cap j and denominator open paren g times degree cap c close paren
4

Which statement describes mechanical energy?

A
the type of energy that is associated with electromagnetic radiation
B
the sum of the kinetic energy and the potential energy of an object
C
the energy that is associated with temperature
D
the energy that is stored in chemical bonds
5

Which energy change takes place when gasoline evaporates from a fuel gas can?

A
Energy is absorbed.
B
Energy remains stationary.
C
Energy becomes transformed.
D
Energy is released.
6

The overall change in enthalpy of a reaction depends only on

A
the reactants and the catalysts only.
B
the path that is taken from the reactants to the products.
C
the reactants and the products.
D
the reactants, the products, and the catalysts.
7

Which defines the average kinetic energy of a system’s particles?

A
volume
B
density
C
temperature
D
pressure
8

A book is falling from the top shelf of a bookcase. Which statement correctly describes the change in the energy of the book?

A
The kinetic energy remains at zero, but potential energy increases.
B
The kinetic energy decreases as potential energy increases.
C
The potential energy and kinetic energy remain the same.
D
The potential energy decreases as kinetic energy increases.
9

The molar heat of fusion of gold is 12 point 5 5 0 kJ mol inverse At its melting point, how much mass of melted gold must solidify to release 235 point 0 kJ of energy? Use q is equal to n triangle cap h

A
222 point 5 g
B
3 comma 688 point 3 g
C
18 point 7 3 g
D
2 comma 949 point 3 g
10

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

A
the product of the enthalpy changes of the intermediate reactions.
B
the difference between the enthalpies of the intermediate reactions.
C
the fraction of the individual enthalpies of the intermediate reactions.
D
the sum of the enthalpy changes of the intermediate reactions.
11

Propane cap c sub 3 cap h sub 8 g , Δ⁢H_f=−103.8kJ/mol reacts with oxygen to produce carbon dioxide CO sub 2 , Δ⁢H_f=−393.5kJ/mol and water cap h sub 2 cap o , Δ⁢H_f=−241.82kJ/mol according to the equation. cap c sub 3 cap h sub 8 g plus 5 cap o sub 2 g rightarrow 3 CO sub 2 g plus 4 cap h sub 2 cap o g What is the enthalpy of combustion (per mole) of cap c sub 3 cap h sub 8 g ? Use Δ⁢H_rxn=∑(Δ⁢H_f_1p⁢r⁢o⁢d⁢u⁢c⁢t⁢s)−∑(Δ⁢H_f_1r⁢e⁢a⁢c⁢tan⁡t⁢s)

A
2 comma 044 point 0 kJ over mol
B
531 point 5 kJ over mol
C
negative 531 point 5 kJ over mol
D
negative 2 comma 044 point 0 kJ over mol
12

Carbon reacts with oxygen to produce carbon dioxide CO sub 2 times g , Δ⁢H_f=−393.5kJ/mol according to the equation. cap c times s plus 2 cap o sub 2 g rightarrow CO sub 2 times g What is the enthalpy change of the reaction? Use Δ⁢H_rxn=∑(Δ⁢H_f_1p⁢r⁢o⁢d⁢u⁢c⁢t⁢s)−∑(Δ⁢H_f_1r⁢e⁢a⁢c⁢tan⁡t⁢s)

A
negative 393 point 5 kJ
B
negative 196 point 8 kJ
C
393 point 5 kJ
D
196 point 8 kJ

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