Chem B2A
Exam 2A
Name:____________________
Section___________________
MULTIPLE CHOICE
1.
Which of the following is not a sign that a chemical reaction has occurred?
a. gas bubbles forming when two substances are mixed
b. the formation of a solid in a clear solution
c. heat being released
d. the absorption of light
e. a change in color
2.
Whose elementary atomic theory requires that all chemical equations must be balanced?
a. Aristotle’s
b. Dalton’s
c. Einstein’s
d. Lavoisier’ s
e. Bohr’s
3.
Refer to the chemical equation:
___ C3H8(g) + ___ 02(g)
___ C02(g) + __ H20(l)
In the correctly balanced equation, what are the coefficients for C3H8 (g), O2 (g), CO2 (g), and H2O
(l), respectively?
a. 1, 1, 1, and 4
b. 1, 10, 3, and 4
c.
1, 3, 3, and 4
d. 1, 1, 3, and 4
c.
1, 5, 3, and 4
4.
Supply the missing coefficient and chemical formula in the following incomplete chemical
equation.
2 PbO (s)
2 Pb (s) + ___ _____
a.
2O(g)
b. O(g )
c. 1/2O2(g)
d.
O2(g)
e. 1/3O3(g)
P
5.
Potassium metal reacts with liquid water to form aqueous potassium hydroxide and hydrogen gas.
Which of the following is the balanced chemical equation for this process?
a. 2K(s) + 2H2O(l)
2KOH(aq) + H2(g)
b. K(s) + H2O(l)
KOH(aq) + H2(g)
c. K(s) + H2O(l)
KOH(aq) + H(g)
d. 2P(s) + 2H2O(l)
2POH(aq) + H2(g)
e. K(s) + 2H2O(l)
K(OH)2(aq) + H2(g)
6.
What type of chemical reaction is the following?
C5H12(l) + 8 02(g)
a.
b.
c.
d.
e.
7.
combination
decomposition
single replacement
combustion
double replacement
What type of chemical reaction is the following?
2 AlI3(aq) + 3C12(g)
a.
b.
c.
d.
e.
8.
5C02(g) + 6H20(l)
2A1C13(aq) + 3I2(s)
combination
decomposition
single replacement
combustion
double replacement
Which of the following is a combination reaction?
a. BaCO3(s)
BaO(s) + CO 2(g)
b. CH4(g) + 2O2(g)
CO2(g) + H2O(g)
c. N2(g) + 3H2(g)
2NH3(g)
d. A12O3(s) + 2Fe(s)
2Al(s) + Fe2O3(s)
e. H2S(aq) + 2KOH(aq)
K2S(aq) + 2H2O(l)
9. Translate the following into a correct balanced chemical equation. Aqueous silver nitrate and
aqueous hydrochloric acid react to form solid silver chloride and aqueous nitric acid.
a.
b.
c.
d.
e.
AgNO3(aq) + HC1(aq)
AgNO2(aq) + HC1(aq)
AgNO3(aq) + 2HC1(aq)
AgN(aq) + HC1(ag)
Ag2NO3(aq) + 2HClO(aq)
AgCl(s) + HNO3(ag)
HNO2(aq) + AgCl(s)
AgC12(s) + H2N03(aq)
AgC1(s) + HN(aq)
Ag(ClO)2(s) + HNO3(aq)
10. What is the definition of the atomic mass unit?
a. 1/16 of the mass of an oxygen-16 atom
b. 1/12 of the mass of a carbon-12 atom
c. the mass of a proton
d. the mass of an electron
e. the mass of a neutron
11. Hydrogen sulfide is a toxic, foul-smelling gas. How many molecules of H2S are in 3.50 mol
H2S?
a. 2.11 x 10-24
b. 5.81 x 10-24
c. 2.11 x 1024
d. 2.11
e. 6.02 x 1023
12. What is the molar mass of copper?
a. 63.5 g
b. 35.0 g
c. 12.0 g
d. 27.0 g
e. 29.0 g
13. How many mol of CaCO3 are contained in 25.0 g of CaCO3?
a.
b.
c.
d.
e.
0.25
1.00
25.0
0.50
2.00
mol
mol
mol
mol
mol
14. A compound was analyzed and found to contain 47.55 percent chlorine and 52.45 percent
potassium. What is the empirical formula of the compound?
a. KBr
b. K2Br
c. KBr2
d. K2Br2
e. 2KBr
15. A compound has the empirical formula C5H40 and a molecular weight of about 240 amu. What is
the molecular formula of this compound?
a. 3C5H40
b.
C5H40
c.
C15H40
d.
C15H1203
16. Phosphorus trichloride, which is used as a starting material in the production of pesticides, is a
highly irritating material. PCl3 can be made from the direct reaction of phosphorus and chlorine
according to the balanced equation:
P4 (s) + 6C12 (g)
4PC13 (g)
How many molecules of PCl3 are produced when one molecule of P4 reacts?
a. 7
b. 1
c. 4
d. 10
e. 11
17. The balanced chemical equation for the neutralization of hydrochloric acid with magnesium
hydroxide is:
Mg(OH)2 + 2HC1
2H20 + MgCl2
How many mol of magnesium hydroxide is required to neutralize 0.250 mol of HC1?
a. 1.00
b. 0.125
c. 0.500
d. 2.00
e. 8.00
18. Use the balanced chemical equation in the above problem to work the following problem.
How many grams of HCl are required to react exactly with 58 g of Mg(OH)2?
a.
19.
7.09
b. 70.9
c. 35.5
d.
24.0
e.
18.0
In the reaction in question 17 calculation was made shoing that 25 g of MgCl2 should be produced.
When the product was weighed only 22.5 gram was recovered. What is the percent recovery?
Show calculations.
20. What is an electron orbital?
a.
b.
c.
d.
e.
a well-defined distance where an electron is found
a region in space around the atomic nucleus in which the electron is likely to be found
a definite path that the electron follows
a region inside the atomic nucleus in which an electron is likely to be found
a very definite orbit in which an electron is found
21. Which of the following is the electron configuration for N?
a.
b.
c.
d.
e.
22.
1s22s22p1
1s22s22p2
1s22s22p3
1s22s22p4
1s22s22p5
How many orbitals are contained in the principle energy shell designated by n = 3?
a. 1
b. 9
c. 18
d. 3
e. 32
23. What element has the following electronic configuration?
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p4
a. S
b. Se
c. Te
d. Ge
e. As
24. Which element from the following list would have atoms of the largest radius?
a. potassium
25.
b. sodium
c. beryllium
d. magnesium
e. calcium
Explain the Bohr theory of the atom.
25. What is likely to have happened when an electron in an atom undergoes a transition from a lower
energy state to a higher energy state?
26.
List five signs that a reaction has taken place.
27. List five symbols included in a chemical reaction and tell what they represent?
28. Write the Lewis dot structures of the elements in period 2 of the periodic chart and indicate how
many bonds each would be expected to form.
29. Explain how ionic bonding and covalent bonding are different
30 Are you ready for the test to be over? Yes_____
No______
Match the following terms and definitions:
1. Reactant
___ Yields hydrogen ions in water.
2. Product
___ Changes the rate of a reaction
3. Chemical Equation
___ Positively charged ion
4. Combination Reaction
___ Reaction with oxygen, pure or in air.
5. Decomposition Reaction
___ Maximum product that can be recovered in a reaction.
6. Single Replacement Reaction ___ Use of balanced equation for reaction calculations.
7. Activity Series
___ Discrete packet of energy in the form of light.
8. Catalyst
___ Chemical substance involved at the start of a reaction.
9. Precipitate
___ Wave function for an electron in an atom.
10. Double Replacement Reaction ___ Mass of one mole of substance.
11. Insoluble
___ Yields a hydroxide ion in water
12. Acid
___ Reactant that is used up first when a reaction goes to completion.
13. Base
___ Mass standard and basis of Avogadro’s number.
14. Salt
___ Solid formed when a reaction takes place.
15. Combustion Reaction
___ Arrangement of elements according to their chemical activity.
16. Neutralization
___ Reaction represented by AB + C ------> AC + B
17. Coefficients
___ Special double replacement reaction between acid and base.
18. Mole
___ Mass of product actually recovered in a reaction.
19. Avogadro’s Number
___ Exact amount required in a reaction.
20. Formula Weight
___ Reaction represented by AB + CD -----> AC + BD
21. Molar Mass
___Electrons do not pair up until all orbitals have an electron.
22. Empirical Formula
___Set of orbitals of approximately the same size and energy.
23. Molecular Formula
___Material formed along with water in a neutralization reaction.
24. Actual Yield
___ Energy required to remove an electron from an atom.
25. Limiting Reactant
___ Properties of elements arranged in numerical order repeat.
26. Line Spectrum
___ States that an orbital can hold no more than two electrons.
27. Stoichiometry
___ Subset of orbitals with same shape and energy level.
28. Theoretical Yield
___ 6.022 x 1023 molecules.
29. Stoichiometric Quantity
___ Number in front of a formula in a chemical equation.
30. Electron Shell
___ Equation represented by C -------> A + B
31. Electron Configuration
___ Material resulting from a chemical reaction.
32. Subshell
___ Distribution of electrons among the different subshells.
33. Photon
___ Reaction represented by A + B--- > C
34. Hund’s Rule
___ Formula with smallest possible whole number subscripts.
35. Pauli’s Exclusion Principle ___ A material that will not dissolve.
36. Periodic Law
___ Symbolic way of representing a chemical reaction.
37. Ionization Energy
___ Sum of atomic weights of all atoms in a formula unit.
38. Carbon Twelve
___ Negatively charged atom or unit made up of atoms.
39. Cation
___ Elements with similar properties on the periodic chart.
40. Anion
___ A horizontal row of elements on the periodic chart.
41. Period
___One of the allowed energy values an electron can have.
42. Chemical Group
___ Element first discovered on the sun.
43. Energy Levels
___ Mass of material containing Avogadro’s number of units.
44. Helium
___ Sum of the mass of all atoms in a formula in amus.
45. Orbital
___Actual formula of a molecule (multiple of empirical formula).