Download Atomic Theory Practice Test

Chem Final Practice: Atomic Theory - Stoichiometry
Atomic Theory Practice Test
Multiple Choice: Identify the letter of the choice that best completes the statement or answers the question.
____
1. If 6 g of element K combine with 17 g of element L, how many grams of element K combine with 85 g of
element L?
a. 17 g
c. 30 g
b. 23 g
d. 91 g
____
2. The principles of atomic theory recognized today were conceived by
a. Avogadro.
c. Dalton.
b. Bohr.
d. Rutherford.
____
3. Rutherford fired positively charged particles at metal foil and concluded that most of the mass of an atom
was
a. in the electrons.
c. evenly spread throughout the atom.
b. concentrated in the nucleus.
d. in rings around the atom.
4. The nucleus of an atom has all of the following characteristics EXCEPT that it
a. is positively charged.
c. contains nearly all of the atom's mass.
b. is very dense.
d. contains nearly all of the atom's volume.
5. The mass of a neutron is
a. about the same as that of a proton.
c. double that of a proton.
b. about the same as that of an electron.
d. double that of an electron.
6. An atom is electrically neutral because
a. neutrons balance the protons and electrons.
b. nuclear forces stabilize the charges.
c. the numbers of protons and electrons are equal.
d. the numbers of protons and neutrons are equal.
7. Most of the volume of an atom is occupied by the
a. nucleus.
c. electron cloud.
b. nuclides.
d. protons.
____
____
____
____
____
____
____
____
____
8. Isotopes of an element contain different numbers of
a. electrons.
c. neutrons.
b. protons.
d. nuclides.
9. An Avogadro's constant amount of any element is equivalent to
a. the atomic number of that element.
c. 6.022  1023 particles.
b. the mass number of that element.
d. 100 g of that element.
10. A quantity of sodium (atomic mass 22.99 amu) contains 6.02  1023 atoms. The mass of the sodium is
a. 6.02  1023 g.
c. 22.99 g.
b. 3.88 g.
d. not determinable.
11. The mass of a sample containing 3.5 mol of silicon atoms (atomic mass 28.0855 amu) is
a. 28 g.
c. 72 g.
b. 35 g.
d. 98 g.
12. How many moles of Hydrogen are there if you have 9.03  1024 Hydrogen atoms?
a. 1.50 mol
c. 10.0 mol
b. 9.03 mol
d. 15.0 mol
____ 13. A prospector finds 39.39 g of gold (atomic mass 196.9665 amu). She has
a. 1.20  1023 atoms.
c. 4.30  1023 atoms.
b. 2.30  1023 atoms.
d. 6.02  1023 atoms.
Ionic Bonding
Multiple Choice: Write the letter that best answers the question (1pt each)
____ 14. Why do atoms form chemical bonds?
a. To gain energy
c. To move faster
b. To become more stable
d. To increase vibration
____ 15. What is an ionic bond?
a. the atoms share electrons evenly
c. the atoms share electrons, but not evenly
b. the atoms take or give electrons
d. the atoms give or take protons
____ 16. Given the compound CO2, what type of bond is it? Electronegativities are C=2.5 O=3.5
a. Non-Polar Covalent
c. Metallic
b. Ionic
d. Polar-Covalent
____ 17. Which of the below is the correct chemical formula for Lead (IV) sulfide?
a. Pb2S4
c. PbS2
b. PbS4
d. Pb4S2
Covalent Bonding
Multiple Choice: (1 pt each)
Identify the letter of the choice that best completes the statement or answers the question.
____ 18. The electrons involved in the formation of a chemical bond are called
a. dipoles.
c. Lewis electrons.
b. s electrons.
d. valence electrons.
____ 19. In a chemical bond, the link between atoms results from the attraction between electrons and
a. Lewis structures.
c. van der Waals forces.
b. the nucleus.
d. isotopes.
____ 20. Atoms are ____ when they are combined.
a. more stable
c. not bound together
b. less stable
d. at a high potential energy
____ 21. The chemical bond formed when two atoms share electrons is called a(n)
a. ionic bond.
c. Lewis structure.
b. orbital bond.
d. covalent bond.
____ 22. The B—F bond in BF3 (electronegativity for B is 2.0; electronegativity for F is 4.0) is
a. polar covalent.
c. nonpolar covalent.
b. ionic.
d. metallic
____ 23. All of the following are true statements about a molecule EXCEPT
a. it is capable of existing on its own.
b. it may consist of two or more atoms of the same type.
c. exist as a crystal lattice.
d. it may consist of two or more atoms of different types.
____ 24. What principle states that atoms tend to form compounds so that each atom can have eight electrons in its
outermost energy level?
a. rule of eights
c. configuration rule
b. Avogadro principle
d. octet rule
2
2
____ 25. The electron configuration of nitrogen is 1s 2s 2p3. How many more electrons does nitrogen need to
satisfy the octet rule?
a. 1
c. 5
b. 3
d. 8
Chemical Reactions
Balance each equation and classify each of the reactions.
Combination, Decompostion, Single Replacement, Double Replacement, or Combusiton.
26. ____ C2H2 + ____ O2
____CO2 + ___ H2O
type: ____________________
.
27. ____ Fe + ____ CuSO4
____ Fe2(SO4)3 + ___ Cu
type: ____________________
.
28. ____ Pb(NO3)2 + ____ K2CrO4
____ PbCrO4 + ___ KNO3
type: ____________________
.
29. ____ Mg(ClO3)2
____ MgCl2 + ___ O2
type: ____________________
.
30. ____ Cu + ____ S8
____ Cu2S
type: ____________________
.
31. ____ C2H5OH + ____ O2
____ CO2 + ___ H2O
type: ____________________
.
32. ____ AgNO3 + ____ CuCl2
____ AgCl + ___ Cu(NO3)2
type: ___________________
Use the periodic table to answer the following questions.
33. Calculate the molar mass of aluminum trifluoride, AlF3. (1 point)
34. Calculate the molar mass of copper(II) sulfate, CuSO4. (1 point)
35. Calculate the percent composition for each element of iron(II) silicate, Fe2SiO4. (3 points)
36. Calculate the percent composition of each element in magnesium chlorate Mg(ClO3)2 . (3 points)
Stoichiometry Problems
37. How many moles of hydrogen are required to react with 2.5 moles of oxygen to produce water?
38. How many moles of HCl, will be required to produce 0.4 moles of hydrogen gas by reaction with
zinc?
39. How many moles on nitrogen and of hydrogen will be required to produce 1.7 moles of ammonia,
NH3?
40. How many moles of fluorine will be needed to produce 5.6 grams of hydrogen fluoride by reaction
with hydrogen?
41. How many grams of carbon will react with 0.25 moles of oxygen to produce carbon dioxide?
42. How many grams of oxygen can be produced when 15.6 grams of sulfur trioxide,SO 3, are
decomposed?
43. How many grams of chlorine are required to produce 355 grams of carbon tetrachloride,CCl4,by
reaction with carbon?
44. How many grams of magnesium are required to react with 1.62 grams of bromine to produce
magnesium bromide,MgBr2?
Limiting Reactant Problems
45. Assume that 2.4 moles of oxygen are reacted with 2.46 moles of magnesium to produce magnesium
oxide, MgO. Determine which reactant is in excess and by what amount, and calculate the
number of moles of product formed.
46. Assume that 13.1 grams of potassium are reacted with 18.0 grams of oxygen to produce potassium
oxide, K2O. Determine which reactant is in excess and by what amount, in moles, and calculate the
number of grams of products formed.