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Chemistry
Name____________________________
Exam1 Quarter 4: Practice Exam
1. State the First Law of Thermodynamics?
2. State the Second Law of Thermodynamics?
3. Suppose you eat an energy bar and then run a mile.
of energy?
a. gravitational potential energy converted into
kinetic (movement) energy
b. chemical potential energy converted into
kinetic (movement) energy
4.
a.
b.
c.
d.
What is the best description of the conversion
c. thermal energy converted into kinetic
(movement) energy
d. solar energy converted into kinetic
(movement) energy
What happens when you break chemical bonds?
the reaction is endothermic because energy flows from the surroundings into the system
the reaction is exothermic because energy flows from the surroundings into the system
the reaction is endothermic because energy flows from the system to the surroundings
the reaction is exothermic because energy flows from the system to the surroundings
5. Draw three energy diagrams for the exothermic reaction shown below. You will draw one for H,
one for S, and one for G
H2O (g)

G = -25 kJ
H2O (l)
G
S
H
time
time
time
6. Which reaction below would be the best choice for producing useful work (like pushing a piston)?
a. a reaction that produces heat (and no gas)
c. a reaction that turns two solids into a liquid
when two liquids are mixed
d. a reaction that produces a gas from two
b. the condensation of a gas into a liquid
liquids
7. The combustion of octane (C8H18, a component of gasoline) is shown below along with the
enthalpy change for the reaction. How many moles of octane would be needed to release 7,500 kJ of
heat?
2C8H18
+
a. 1.5 moles
b. 2.7 moles
25O2

16CO2
+
18H2O
H = -5,530 kJ/mole of reaction
c. 16 moles
d. 25 moles
8. The symbol S denotes which thermodynamic term?
a. enthalpy
c. Gibb’s free energy
b. thermal heat transferred
d. entropy
9. What can be said if a chemical reaction is considered ‘non-spontaneous’?
a. the reaction if fast
c. the reaction is slow
b. G = positive
d. G = negative
10. For a given reaction conducted at -150 C, the following data was collected: H = +2.5 kJ and S
= +315 J/K. Calculate G using the Gibb’s Free Energy equation and express your answer in joules.
You must show your work for full credit.
11. A constant volume calorimeter is also known as what?
a. bomb
c. test tube
b. beaker
d. coffee cup
12. Examine the reaction below and select the best choice that follows.
a. the reaction is exothermic
b. the reaction can perform work (like pushing
a piston)
c. the reaction is endothermic
d. the reaction feels cold
13. Recall that heat flow out of a system at constant pressure is equal to the enthalpy change H and
can be calculated by the equation shown below when using a coffee cup calorimeter. Given an initial
temperature of 23.2 C of 55 grams of a water in the calorimeter (whose specific heat Cs is 4.184
J/gC) and an observed ∆H = +1,252 joules, what was the final temperature (in degrees Celsius) of the
water in the coffee cup calorimeter? Show all work for full credit.
∆H = mC∆T
14. Which of the following is true of equilibria reactions in chemistry?
a. reactions with a large, positive Keq proceed very quickly
b. all particle movement stops when equilibrium is reached
c. particles are continuously moving back and forth between reactants and products
d. the state of equilibrium only applies to chemical changes
15. Write a Keq expression for the balanced combustion reaction shown in the space provided
below. (3 pts)
2C2H6 (g) + 7O2 (g) ⇌ 4CO2 (g) + 6H2O (l)
Keq = ______________________
Use the following information to provide to answer questions 16-17 below: the gases nitrogen
and fluorine react to give the gaseous product nitrogen trifluoride.
16. In the space below, write a balanced equilibrium equation for the chemical process
described in words above. (3 points)
17. In the space provided, use the balanced equation you wrote for question 16 to write a Keq
expression for this process.
(3 points)
Keq = ______________________
Use the information below to answer questions 18-19. The reaction is modeled by the
equilibrium equation and Keq expression shown below.
2N2 (g) + 3O2 (g) ⇌ 2N2O3 (g)
Keq = [N2O3]2
[N2]2[O2]3
18. Calculate the value of Keq if the equilibrium values for each gas are as follows: [N2O3] =
2.5M; [N2] = 0.01M; [O2] = 0.05M. Use the spaces provided to break the problem down into
steps; place your final answer in the box.
(4 points)
Keq = ___________________ = ____________________ =
19. The Keq value calculated in question 18 above indicates the equilibrium reaction may be
considered which of the following?
a. reactant-favored
b. product-favored
c. neither reactant- nor product-favored
20. Fill in the table below with the appropriate definitions.
Definition
Arrhenius
Bronsted-Lowry
Acid
Base
21. Examine the reaction below and circle the correct choice for each question. LiOH is lithium
hydroxide.
LiOH  OH- + Li+
a. Lithium hydroxide is a(n) (acid/base)
[circle one]
b. Lithium hydroxide best fits the (Arrhenius/Bronsted-Lowry) definition
[circle one]
c. an aqueous solution of LiOH would have a pH of (greater than/less than) 7
[circle one]
22. Examine the reaction below between an unknown substance B and a proton. How would you best
characterize unknown substance B?
B + H+

BH+
a. substance B is only an Arrhenius base
b. substance B is both an Arrhenius acid and a Bronsted-Lowry acid
c. substance B is only a Bronsted-Lowry base
d. substance B is both an Arrhenius base and a Bronsted-Lowry base
23. Phosphoric acid, H3PO4, is both a Bronsted-Lowry acid and an Arrhenius acid. This acid is found
in Coca-Cola ®. Which statement is correct concerning phosphoric acid?
H3PO4
a. phosphoric acid is a weak acid
b. phosphoric acid is a weak base
H+
+
H2PO4c. phosphoric acid is a strong acid
d. phosphoric acid is a strong base
24. Which of the following is correct concerning a solution of NaOH (a component of Drano ®)?
a. the pH should be less than 7 because it is a
c. the pH should be greater than 7 because it is
base
a base
b. the pH should be less than 7 because it is an
d. the pH should be greater than 7 because it
acid
is an acid
25. Calculate the pH for a solution whose proton concentration, [H+], is 5.4 x 10-6 M? Show your
work for full credit.
26. How would you describe the solution in question 27?
a. it is an acid
b. it is a base
27. Which of the following best describes what happens to protons once they are formed in water?
a. they turn into hydroxide ions, OHc. they turn into neutrons
+
b. they turn into hydronium ions, H3O
d. they turn into water molecules, H2O
28. When an acid neutralizes an Arrhenius base, which of the following best describes the products?
a. formation of water and an ionic compound
c. formation of hydrogen bond
called a ‘salt’
d. formation of a non-metal
b. formation of a water and a covalent
compound
29. Consider the neutralization reaction shown below. How many liters of 0.05 M KOH (potassium
hydroxide) are needed to neutralize 0.04 liters of 0.07M HCl (hydrochloric acid)? Show all work.
HCl
+
KOH

H2O
+
KCl
30. What will be the pH of the solution in problem 29 after the neutralization?_________________