Semester I Review Problems
E=
8
h = 6.6262 x 10 -34 Js
c = 2.998 x 10 m/s
10-9m = 1nm
1amu = 1.6606 x 10-24 g
1. Classify each of the following as element, compound, or mixture.
a) air
b) table salt
c) milk
d) mercury
2. Classify as heterogeneous or homogeneous
a) ranch dressing
c) gasoline
b) oatmeal raisin cookie dough
d) seawater
3.
a)
b)
c)
d)
The following data refer to the element phosphorus. Classify each as a physical or chemical property.
It exists as white, red and black phosphorus
It is a solid at 25°C
It is insoluble in water
It burns in chlorine to form phosphorus trichloride
4. Who discovered the nucleus? Describe the experiment that led to the discovery.
5. Iodine is a dark purple solid.
a) What is its formula?
b) How many protons and electrons are there in a molecule of iodine? How many in an iodide ion?
c) What is the atomic number for iodine?
d) How many neutrons does an atom of iodine have? (Assume no isotopes)
e) In what group and period does iodine belong in the periodic table? Is it a metal, nonmetal or metalloid?
6. Give the symbols for:
a) cesium
b) tungsten
c) antimony
7. Name the elements whose symbols are: a) C
d) krypton
b) Co
c) Cd
e) potassium
d) Cl
e) Cu
8. Classify the elements in questions 6 and 7 as metals, nonmetals or metalloids. Also state if they are halogens
alkali metals, alkaline earth metals or noble gases.
9. Name these compounds: a) N2H4
b) NaClO3
e) Fe3(PO4) 2
g) K2CO3
f) IF7
c) BrF5
d) NCl3
10. Write formulas for these compounds:
a) calcium bromide
b) aluminum sulfide
c) tin(IV) cyanide
d) strontium acetate
f) nitrogen dioxide
e) silver chloride
11. Give the electron configuration (short and long) of:
a) S
b) K
c) Ti
d) Cl
12. How many unpaired electrons would be found in a) Mg
b) P
13. Choose the larger particle in each pair: a) Na or Si
b) P or Sb
e) Sb
f) Ba
c) V
c) Na or N
d) Cl or As
14. Ozone shields us mostly from UV light having a wavelength of 295 nm. What is the energy of this light?
15. Complete the following table:
Symbol
# of neutrons
136
56
Ba
# of protons
# of electrons
25
25
Atomic #
Mass #
2
120
79
21
20
56
79
18
16. Sodium vapor lamps are often used in residential street lighting. They give off a yellow light having an
energy of 3.37 x 10-19 J. What is the wavelength of this light?
17. Calculate the energy of a photon of green light with a wavelength of 550 nm.
18. Give Lewis structures for: a) CS2
e) TeF2
f) AsH3
b) CN-
c) SeO3
g) PCl4+
d) H3O+
h) CO3-2
19. Predict the geometry and bond angles (where applicable) of the molecules in the above problem and tell
whether the molecules will be polar or not.
20. The Lewis structure of CO2 typically contains two double bonds; however, two other resonance structures
can also be drawn for it. What are they?
21. Identify the following bonds as polar covalent, nonpolar covalent or ionic:
a) Hg-P
b) P-S
c) Si-F
d) Mg-N
e) Fe-N
22. Draw a diagram showing why the molecule SO2 is polar.
23. At 25ºC, hydrogen molecules travel at an average speed of 1770 meters per second. What is this speed in
kilometers per hour?
24. A drop of water contains approximately 1.70 x 1021 molecules. If the water were evaporating at the rate of
1,830,000 molecules per second, how many years would it take for the molecules in one drop of liquid water to
completely become gas molecules?
25. One querk contains 2.0 warts, 3.0 querks makes 1.0 zags, 5.0 zags are found in 6.0 nerfs and 4.0 nerfs join
to make 5.0 wigs. How many warts are in 13 wigs?
26. Gallium has a density of 5.88 g/ml at 27ºC. How many grams of gallium will fill a 25.0 cm3 vessel?
27. Sulfuric acid has a density of 1.86 g/ml. What volume will have a total mass of 97.6 g?
28. If a 3.220 kg cat eats a 213.6 g rat which has just popped a 4.120 mg piece of cheese into its mouth, the cat
will then have a mass of how many kilograms?
29. A technician experimentally determined the boiling point of octane to be 124.1˚C. The theoretical boiling
point of octane is 125.7˚C. What, if anything, can you determine about the precision and accuracy of the
technician’s work?
30. Neon has three different isotopes. 90.51% of neon atoms have a mass of 19.992 amu. 0.2700% of neon
atoms have a mass of 20.994 amu. 9.22% of neon atoms have a mass of 21.991 amu. What is the average
atomic mass of neon?
31. A magnesium isotope has a mass of 24.9858 amu. What is its mass in grams? What is the mass of
2.4890x1021 atoms of this isotope?
32. Solid copper (I) sulfide reacts with oxygen gas forming solid copper (I) oxide and sulfur dioxide gas. Write
the balanced equation for this reaction.
33. Aqueous potassium dichromate and aqueous copper (II) chloride react in a double replacement reaction.
Write and balance the reaction showing symbols for solid, liquid, gas and aqueous.
34. The accepted value is 0.865 g/ml. Which correctly describes this student’s
experimental data?
a. accurate but not precise
c. both accurate and precise
b. precise but not accurate
d. neither accurate nor precise
Trial
1
2
3
Measurement
0.887 g/ml
0.672 g/ml
1.036 g/ml
35. What is the correct measurement for the location marked by the arrow?
36. Write net ionic equations for any precipitates resulting from mixtures of these aqueous solutions:
a) KI + (NH4)2CO3
b) Pb(NO3)2 + CaCl2
c) CaS + MgSO4
d) NaOH + HCl
Write balanced molecular equations for these reactions:
37. combustion of tricarbon hexahydride
38. ammonium phosphate and barium hydroxide
39. aluminum and hydrogen chloride
40. sodium sulfate and potassium chloride
41. synthesis of sulfur and lithium
42. sodium phosphide decomposing
Balance these equations and then identify the reaction type and write sentences for these reactions:
43.
CaO +
SiO2 
CaSiO3
44.
Na +
45.
Na2SO4
46.
C12H26
Fe2O3 
+
+
Na2O +
AlCl3 
NaCl
O2 
CO2 +
+
Fe
Al2(SO4) 3
H2O
Identify whether the following mixtures will react. If a reaction will occur, write net ionic equations for any
solid that forms.
47. barium hydroxide and aluminum sulfate
48. ammonium silicate and iron (III) chloride
49. sodium sulfate and aluminum chloride
50. ammonium phosphate and barium hydroxide
51. Classify each of the following substances as polar covalent, nonpolar covalent, ionic or metallic:
a) It is insoluble in water, conducts electricity and has a high melting point
b) It conducts electricity when it is dissolved in water, and melts at high temperatures
c) It is insoluble in water, melts at low temperatures and does not conduct electricity either as a solid or when
dissolved in water.
52. Explain how the bond type of a substance affects its solubility.
53. Capsaicin, the compound responsible for the “heat” of chili peppers, is most easily washed out of your
mouth with fatty drinks like whole milk not with water. What does this tell you about the probable bond type in
the capsaicin molecule?
54. Soap works so well for cleaning because its chemical structure allows it to dissolve in both grease and oil
(nonpolar compounds) and also in water. Which end of this
soap molecule will dissolve in grease and oil and which side
will dissolve in water?