ChemistryChemistryUnit 6 Unit 6 Study GuideStudy GuideYou may use this study guide to review for your test; practice your new skills or review old concepts.

Each topic has several questions relating to it, this should help with giving you plenty of practice.

Exothermic and

Endothermic

A B C

∆H

A B C

Characteristics of a Reaction

A B C

Factors Affecting

Equilibrium

ABC

Keq of reactions-conceptual

A B C

Activation Energy

A B C

Equilibrium

A B C

Keq of reactions-

mathematical

A B C

Exothermic and Endothermic Exothermic and Endothermic AA

In an exothermic reaction is energy

one of the products or one of the reactants?

It is a reactant

Exothermic and Endothermic Exothermic and Endothermic BB

In an endothermic reaction is energy

one of the products or one of the reactants?

It is one of the reactants

Exothermic and Endothermic Exothermic and Endothermic CC

IN the following reaction is it endothermic or exothermic?

CH4 + 2O2 → CO2 + 2H2O + 194 kJ

exothermic

∆∆H H AA

If the H of a reaction is positive is the reaction endothermic or exothermic?

endothermic

∆∆H H BB

If E2 < E1 this reaction is endothermic or exothermic?

exothermic

∆∆HH C C

If the H is negative is the reaction endothermic or exothermic, why?

Exothermic, because the products have more energy than the reactants

Characteristics of a Reaction Characteristics of a Reaction AA

What are the ways that we can identify if a reaction has occurred?

Color change, formation of a precipitate, change in temperature, gas given off

Characteristics of a Reaction Characteristics of a Reaction BB

When heat is produced as a product, explain on a molecular level what is

occurring.The energy required to break the reactants apart is more than the energy given off when the new bonds of the product form and therefore the extra energy is given off as heat.

Characteristics of a Reaction Characteristics of a Reaction CC

Why would the formation of a precipitate be a good indicator of a

chemical reaction?Because the new compound that is being made is insoluble in the solution and therefore settles out as a solid. The original compounds were soluble so since we saw a change in the solubility there must have been a change in the formula.

Factors Affecting Equilibrium Factors Affecting Equilibrium AA

What are the factors that might affect equilibrium?

Change in temperature, change in concentration of reactants or products, pressure of the system

Factors Affecting Equilibrium Factors Affecting Equilibrium BB

If you have an exothermic reaction and you increase the temperature of the system what

will happen to the equilibrium and why?

The equilibrium will shift to the reactants because the endothermic side of the reaction will be favored.

Factors Affecting Equilibrium Factors Affecting Equilibrium CC

If you increase the pressure in a system how will that affect the equilibrium?

The side of the reaction with the fewest number of molecules will be favored.

KKeqeq of Reactions- conceptual of Reactions- conceptual AA

Write the Keq of the following reaction.

CuSO4 + 2HNO3 → Cu(NO3)2 + H2SO4

Keq = [Cu(NO3)2] [H2SO4] [CuSO4] [HNO3]2

KKeqeq of Reactions- conceptual of Reactions- conceptual BB

What is the Keq of the following reaction?

3Ca(OH)2 +2 AlBr3 →3CaBr2 + 2Al(OH)3

Keq = [CaBr2]3 [Al(OH)3]2

[Ca(OH)2]3 [AlBr3]2

KKeq eq of Reactions- conceptual of Reactions- conceptual CC

In the following reaction what do the lowercase letters represent?

aA + bB→ cC + D

The coefficients used to balance the reaction.

Activation Energy AActivation Energy A

What is activation energy?

The energy required to start a chemical reaction.

Activation Energy BActivation Energy B

How can we decrease the activation energy of a reaction?

A catalyst will decrease the amount of activation energy required for a chemical reaction without changing the reaction itself.

Activation Energy CActivation Energy C

Do exothermic reactions have an activation energy? Do spontaneous reactions have

a higher or lower activation energy?

Exothermic reactions have some form of activation energy but spontaneous reactions have such low activation energies that the energy of the environment is enough to start the reaction.

Equilibrium AEquilibrium A

What is equilibrium?

A situation in which a chemical reaction occurs equally in a forward and backward direction. So we are forming products at the same rate that the products are breaking and forming reactants.

Equilibrium BEquilibrium B

Do all reactions reach equilibrium?

If left long enough all reactions will reach equilibrium.

Equilibrium CEquilibrium C

What happens if we change an environmental factor such as increasing the temperature or

pressure?

The equilibrium of the reaction will shift until the new balance is aquired in the new environment.

KKeqeq of Reactions- of Reactions-Mathematical AMathematical A

For the following reaction what is the Keq?

2H2 + O2 → 2H2O

H2= 1.5 M; O2 = 3 M; H2O = 2M

Keq = (2 M )2

(1.5 M)2(3M) = 0.59

KKeqeq of Reactions- of Reactions-Mathematical BMathematical B

Find the Keq for the following reaction.

CH4 + 2 O2 → CO2 + 2H2O

CH4 = 2.1 M; O2 = 1.1 M; CO2 = 3.3 M; H2O = 1.2 M

Keq = (3.3 M)(1.2 M)2

(2.1M)(1.1 M)2 = 1.87

KKeqeq of Reactions- of Reactions-Mathematical CMathematical C

Find the Keq for the following reaction.

NaCl + HOH → HCl + NaOHNaCl= 9.5 M; HOH = 10.0M ; HCl = 4.00M; NaOH = 4.00M

Keq= (4.00M)(4.00M) (9.60M)(10.0) = 0.167