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WorksheetsTerm 1 revision (Gr12)
Total questions: 20
Worksheet time: 41mins
As compared with separate gases, a mixture of gases is ____________
more random.
less random.
equally random.
less favorable.
The study of the transfers of energy that accompany chemical reactions and
physical changes is called (a) .
Free-energy change depends on temperature, entropy change, and (b) change.
Free energy is measured in units called (c) .
The measure of the average kinetic energy of the particles in a sample of
matter is its (d) .
The energy transferred between samples of matter because of a difference in
their temperatures is called (e) .
A compound that is very unstable and likely to decompose violently
has an enthalpy of formation that is ______________
small and negative.
small and positive.
large and negative.
large and positive.
The specific heat of a substance is dependent on the energy lost or gained,
temperature, and (a) .
The enthalpy change is always the difference between the enthalpies of the
(b) and the (c) .
As a general rule, when a substance goes from a liquid to a gas, the entropy
(d) .
When the enthalpy of a reaction is negative and the entropy is positive, the
Gibbs free energy is always (e) .
The (a) is negative for exothermic reactions and
positive for endothermic reactions.
A reaction for which ΔH = -500 kJ is ______
definitely spontaneous.
probably spontaneous.
probably nonspontaneous.
definitely nonspontaneous.
Which of the following is not directly measurable?
enthalpy of formation
enthalpy of combustion
enthalpy
change in enthalpy
An endothermic reaction has
a positive enthalpy change.
a negative enthalpy change.
no enthalpy change.
either a positive or a negative enthalpy change.
Which of the equations below is an example of a thermochemical
equation?
Mg(s) + 2H3O+(aq) + Cl-(aq) →
Mg2+(aq) + 2Cl-(aq) + H2(g) + H2O(l)
Mg + 2H3O+ + Cl- → Mg2+ + 2Cl- + H2 + H2O
2H2(g) + 2O2(g) → H2O(g)
2H2(g) + 2O2(g) → H2O(g) + 483.6 kJ
Match each description with the correct term.
Positive ΔH
Exothermic
Negative change in Gibbs free
energy
Reaction that increases
disorder
Positive change in entropy
Endothermic
Negative change in enthalpy
Spontaneous
Negative ΔS
Reaction that Decreases
disorder
What is the value of ΔG at 120.0 K for a
reaction in which ΔH = +35 kJ/mol and
ΔS = -1.50 kJ/(mol·K)? (Solve and show the steps)
The products in a reaction have an enthalpy of 458kJ/mol, and the reactants
have an enthalpy of 658 kJ/mol.
What is the value of ΔH for this reaction? (Solve with steps)
Calculate the enthalpy of reaction for the combustion of nitrogen monoxide gas,
NO, to form nitrogen dioxide gas, NO2, as given in the following thermochemical
equation.
NO(g) + ½O2(g) → NO2(g)
The known thermochemical reactions and enthalpy data are:
½N2(g) + ½O2(g) → NO(g); ΔHf0 = +90.29 kJ
½N2(g) + O2(g) → NO2(g); ΔHf0 = +33.2 kJ
Find the enthalpy of the reaction of magnesium oxide with hydrogen chloride.
MgO(s) + 2HCl(g) → MgCl2(s) + H2O(l)
Use the following equations and data.
Mg(s) + 2HCl(g) → MgCl2(s) + H2(g) ΔH = −456.9 kJ/mol
Mg(s) + O2(g) → MgO(s) ΔH = −601.6 kJ/mol
H2O(l) → H2(g) + O2(g) ΔH = +285.8 kJ/mol
What is the Gibbs energy change for the following reaction at 25°C?
ΔS = 10.6 J/mol⋅K
ΔHf0 = -425.9 kJ/mol
Which process is used to speed up chemical reactions?
inhibition
activation
catalysis
calorimetry
A catalyst that increases metabolic processes is known as a(n)
activated complex.
rate-determining step.
mechanism.
enzyme.
Catalysts affect reaction rates by
forming an activated complex with higher energy.
changing the net thermodynamics of the reaction.
decreasing the activation energy.
broadening the energy barrier.
What impact does an increase in temperature generally have on the rate
of a reaction?
It increases it.
It has no impact.
There is no way to measure the change.
It decreases it.
Which factor cannot increase the rate of a reaction?
surface area
concentration
temperature
inhibitor.
