Chapter 1
Understanding Our World with Chemistry
2. An element is the simplest form of a pure substance and consists of atoms of a single type. A
compound is a substance that is made up of two or more elements that are chemically bonded
together.
4. A homogeneous mixture is one in which the substances that compose it are so evenly
distributed that a sample from any one part of the mixture will be chemically identical to a
sample from any other part. A heterogeneous mixture is one in which the composition varies
from one region of a sample to another.
Homogeneous Mixture Heterogeneous Mixture
6. When coloring, flavoring, and sweetener are completely dissolved in drinking water, the result
is a homogeneous mixture. Adding carbonation, ice cubes, or a slice of lemon or lime to the
beverage will result in a heterogeneous mixture.
8. The periodic table places an extensive amount of information at your fingertips; it can help
predict the formula of many compounds, relative sizes of atoms and molecules, shapes of
molecules, and whether compounds will dissolve in water or oil (based on polarity). Elements
are arranged periodically in the table for convenient observation of the trends in elemental
properties.
10. The IUPAC (International Union of Pure and Applied Chemistry) is responsible for maintaining
the periodic table of the elements.
1
,2 Chapter 1
12. On the periodic table sketched below, metals are white, nonmetals are light grey, and
metalloids are dark grey.
14. The scientific method is used to solve problems by first identifying the problem, then
collecting and analyzing all relevant information and forming a hypothesis (educated guess).
This hypothesis is then tested and refined until the problem has been satisfactorily solved.
16. Many different professions use the scientific method to solve problems because it is a logical,
systematic way of identifying all information relevant to a situation and using it to make
reasonable conclusions within the context of that information.
18. The container shown has a pure substance made up of a compound. The dark blue spheres
would represent atoms of one element and the light blue spheres would represent atoms of
another element. They are shown with each dark blue sphere connected to one light blue
sphere, indicating that they are compounds.
20. (a) ethanol – pure substance
(b) soda – mixture (water, carbon dioxide, flavors, sweeteners, and dyes)
(c) soil – mixture (clays, rock fragments, and organic materials)
(d) brass – mixture (primarily copper and zinc)
22. (a) sugar – compound (C12H22O11)
(b) carbon – element
(c) lead – element
(d) rust – compound (Fe2O3)
24. (a) river water – heterogeneous mixture
(b) brass alloy – homogeneous mixture
(c) coffee – homogeneous mixture
(d) whiskey – homogeneous mixture
26. (a) Cr – chromium (b) S – sulfur
(c) Cl – chlorine (d) Br – bromine
28. (a) Si – silicon (b) Ti – titanium
(c) Sr – strontium (d) Au – gold (Latin “aurum”)
,Understanding Our World with Chemistry 3
30. (a) sodium – Na (b) aluminum – Al
(c) vanadium – V (d) uranium – U
32. (a) zirconium – Zr (b) mercury – Hg
(c) bismuth – Bi (d) palladium – Pd
34. (a) sulfur, S (not sulfer, Su)
(b) aluminum, Al is correct
(c) manganese, Mn is correct
(d) boron, B (not Bo)
36. (a) antimony – metalloid (b) tellurium – metalloid
(c) thorium – metal (d) selenium – nonmetal
38. (a) Cd – metal (b) Po – metal
(c) Cl – nonmetal (d) Po – metal
40. (b) Na3PO4 contains three sodium atoms, one phosphorus atom, and four oxygen atoms.
42. (a) 1 lithium atom, 1 nitrogen atom, 3 oxygen atoms – LiNO3
(b) 2 potassium atoms, 1 sulfur atom – K2S
(c) 1 nitrogen atom, 4 hydrogen atoms, 1 chlorine atom – NH4Cl
(d) 2 carbon atoms, 6 hydrogen atoms – C2H6
44. (d) Eliminate conflicting data – in the scientific method, it is especially important to pay
attention to conflicting data and NOT eliminate it; it is a sign that the hypothesis needs to be
reexamined and probably altered.
46. The center-to-center distance between adjacent letters should be the same throughout. The
document pictured used a more advanced printing press that compressed the spaces between
adjacent letters by having different sized blocks for each of the letters.
48. Sludge might contain heavy metals. A controlled analysis for heavy metals would involve
construction of a standard curve, some sort of chemical digestion step to break down organic
material, and then finally analysis of the suspected material. In addition, there may be
bacterial contamination in the sludge from the fecal coliform bacteria in fecal matter. A
controlled analysis for such organisms would require a sterile solution as control and then
several representative samples from the sludge itself. (There are multiple examples of good
ways to use the scientific method to approach this problem; I have only included two simple
examples.)
50. (The instructor will have to judge the quality of answers to this question. There are simply too
many medical dramas and forensic-science crime teams on television, and they are all so
inaccurate that they stretch credibility at the very least.)
, Chapter 2
Matter: Properties, Changes, and Measurements
2. An example of a chemical process is converting carbohydrates into ATP (usable energy) to
“run” your body. An example of a physical process is when rain freezes and turns into
snow/ice.
4. Examples of chemical properties include flammability, rusting, and explosiveness.
6. The unit of a measurement contains critical information about what system of measurement is
used and whether the base unit is modified with a prefix.
8. 1 mL (milliliter) = 1 cc (cubic centimeter) = 1 cm3 (centimeter cubed).
10. A conversion factor is used by dividing by the units you wish to cancel and multiplying by the
units you want in the final answer. It is a mathematical method of using proportionalities to
convert from one unit to another.
12. Whenever you make a measurement, you basically are sure of all digits except the last one,
which can change based on observations between people. This is the inherent error in any
measurement.
14.
Accurate and Precise Precise but Not Accurate Neither Accurate nor Precise
16. (a) Formation of clouds and rain is a physical change.
(b) Freezing biological samples for storage is a physical change.
(c) Baking bread dough is a chemical change.
(d) Detonation of TNT is a chemical change.
18. (a) Refractive index is a physical property.
(b) Boiling point is a physical property.
(c) Explosiveness is a chemical property.
(d) Inertness is a chemical property.
4
Understanding Our World with Chemistry
2. An element is the simplest form of a pure substance and consists of atoms of a single type. A
compound is a substance that is made up of two or more elements that are chemically bonded
together.
4. A homogeneous mixture is one in which the substances that compose it are so evenly
distributed that a sample from any one part of the mixture will be chemically identical to a
sample from any other part. A heterogeneous mixture is one in which the composition varies
from one region of a sample to another.
Homogeneous Mixture Heterogeneous Mixture
6. When coloring, flavoring, and sweetener are completely dissolved in drinking water, the result
is a homogeneous mixture. Adding carbonation, ice cubes, or a slice of lemon or lime to the
beverage will result in a heterogeneous mixture.
8. The periodic table places an extensive amount of information at your fingertips; it can help
predict the formula of many compounds, relative sizes of atoms and molecules, shapes of
molecules, and whether compounds will dissolve in water or oil (based on polarity). Elements
are arranged periodically in the table for convenient observation of the trends in elemental
properties.
10. The IUPAC (International Union of Pure and Applied Chemistry) is responsible for maintaining
the periodic table of the elements.
1
,2 Chapter 1
12. On the periodic table sketched below, metals are white, nonmetals are light grey, and
metalloids are dark grey.
14. The scientific method is used to solve problems by first identifying the problem, then
collecting and analyzing all relevant information and forming a hypothesis (educated guess).
This hypothesis is then tested and refined until the problem has been satisfactorily solved.
16. Many different professions use the scientific method to solve problems because it is a logical,
systematic way of identifying all information relevant to a situation and using it to make
reasonable conclusions within the context of that information.
18. The container shown has a pure substance made up of a compound. The dark blue spheres
would represent atoms of one element and the light blue spheres would represent atoms of
another element. They are shown with each dark blue sphere connected to one light blue
sphere, indicating that they are compounds.
20. (a) ethanol – pure substance
(b) soda – mixture (water, carbon dioxide, flavors, sweeteners, and dyes)
(c) soil – mixture (clays, rock fragments, and organic materials)
(d) brass – mixture (primarily copper and zinc)
22. (a) sugar – compound (C12H22O11)
(b) carbon – element
(c) lead – element
(d) rust – compound (Fe2O3)
24. (a) river water – heterogeneous mixture
(b) brass alloy – homogeneous mixture
(c) coffee – homogeneous mixture
(d) whiskey – homogeneous mixture
26. (a) Cr – chromium (b) S – sulfur
(c) Cl – chlorine (d) Br – bromine
28. (a) Si – silicon (b) Ti – titanium
(c) Sr – strontium (d) Au – gold (Latin “aurum”)
,Understanding Our World with Chemistry 3
30. (a) sodium – Na (b) aluminum – Al
(c) vanadium – V (d) uranium – U
32. (a) zirconium – Zr (b) mercury – Hg
(c) bismuth – Bi (d) palladium – Pd
34. (a) sulfur, S (not sulfer, Su)
(b) aluminum, Al is correct
(c) manganese, Mn is correct
(d) boron, B (not Bo)
36. (a) antimony – metalloid (b) tellurium – metalloid
(c) thorium – metal (d) selenium – nonmetal
38. (a) Cd – metal (b) Po – metal
(c) Cl – nonmetal (d) Po – metal
40. (b) Na3PO4 contains three sodium atoms, one phosphorus atom, and four oxygen atoms.
42. (a) 1 lithium atom, 1 nitrogen atom, 3 oxygen atoms – LiNO3
(b) 2 potassium atoms, 1 sulfur atom – K2S
(c) 1 nitrogen atom, 4 hydrogen atoms, 1 chlorine atom – NH4Cl
(d) 2 carbon atoms, 6 hydrogen atoms – C2H6
44. (d) Eliminate conflicting data – in the scientific method, it is especially important to pay
attention to conflicting data and NOT eliminate it; it is a sign that the hypothesis needs to be
reexamined and probably altered.
46. The center-to-center distance between adjacent letters should be the same throughout. The
document pictured used a more advanced printing press that compressed the spaces between
adjacent letters by having different sized blocks for each of the letters.
48. Sludge might contain heavy metals. A controlled analysis for heavy metals would involve
construction of a standard curve, some sort of chemical digestion step to break down organic
material, and then finally analysis of the suspected material. In addition, there may be
bacterial contamination in the sludge from the fecal coliform bacteria in fecal matter. A
controlled analysis for such organisms would require a sterile solution as control and then
several representative samples from the sludge itself. (There are multiple examples of good
ways to use the scientific method to approach this problem; I have only included two simple
examples.)
50. (The instructor will have to judge the quality of answers to this question. There are simply too
many medical dramas and forensic-science crime teams on television, and they are all so
inaccurate that they stretch credibility at the very least.)
, Chapter 2
Matter: Properties, Changes, and Measurements
2. An example of a chemical process is converting carbohydrates into ATP (usable energy) to
“run” your body. An example of a physical process is when rain freezes and turns into
snow/ice.
4. Examples of chemical properties include flammability, rusting, and explosiveness.
6. The unit of a measurement contains critical information about what system of measurement is
used and whether the base unit is modified with a prefix.
8. 1 mL (milliliter) = 1 cc (cubic centimeter) = 1 cm3 (centimeter cubed).
10. A conversion factor is used by dividing by the units you wish to cancel and multiplying by the
units you want in the final answer. It is a mathematical method of using proportionalities to
convert from one unit to another.
12. Whenever you make a measurement, you basically are sure of all digits except the last one,
which can change based on observations between people. This is the inherent error in any
measurement.
14.
Accurate and Precise Precise but Not Accurate Neither Accurate nor Precise
16. (a) Formation of clouds and rain is a physical change.
(b) Freezing biological samples for storage is a physical change.
(c) Baking bread dough is a chemical change.
(d) Detonation of TNT is a chemical change.
18. (a) Refractive index is a physical property.
(b) Boiling point is a physical property.
(c) Explosiveness is a chemical property.
(d) Inertness is a chemical property.
4
