SAMPLE EXERCISE 1.1 Distinguishing among Elements, Compounds, and Mixtures
“White gold,” used in jewelry, contains two elements, gold and palladium. Two different samples of white gold
differ in the relative amounts of gold and palladium that they contain. Both are uniform in composition
throughout. Without knowing any more about the materials, use Figure 1.9 to characterize and classify white
gold.
Solution Because the material is uniform throughout, it is homogeneous. Because its composition differs for
the two samples, it cannot be a compound. Instead, it must be a homogeneous mixture. Gold and palladium can
be said to form a solid solution with one another.
PRACTICE EXERCISE
Aspirin is composed of 60.0% carbon, 4.5% hydrogen, and 35.5% oxygen by mass, regardless of its source. Use
Figure 1.9 to characterize and classify aspirin.
Answer: It is a compound because it has constant composition and can be separated into several elements.
, SAMPLE EXERCISE 1.2 Using Metric Prefixes
What is the name given to the unit that equals (a) 10–9 gram, (b) 10–6 second, (c) 10–3 meter?
Solution In each case we can refer to Table 1.5, finding the prefix related to each of the decimal fractions: (a)
nanogram, ng, (b) microsecond, s (c) millimeter, mm.
PRACTICE EXERCISE
(a) What decimal fraction of a second is a picosecond, ps? (b) Express the measurement 6.0 103 m using a
prefix to replace the power of ten. (c) Use exponential notation to express 3.76 mg in grams.
Answers: (a) 10–12 second, (b) 6.0 km, (c) 3.76 10–3 g
“White gold,” used in jewelry, contains two elements, gold and palladium. Two different samples of white gold
differ in the relative amounts of gold and palladium that they contain. Both are uniform in composition
throughout. Without knowing any more about the materials, use Figure 1.9 to characterize and classify white
gold.
Solution Because the material is uniform throughout, it is homogeneous. Because its composition differs for
the two samples, it cannot be a compound. Instead, it must be a homogeneous mixture. Gold and palladium can
be said to form a solid solution with one another.
PRACTICE EXERCISE
Aspirin is composed of 60.0% carbon, 4.5% hydrogen, and 35.5% oxygen by mass, regardless of its source. Use
Figure 1.9 to characterize and classify aspirin.
Answer: It is a compound because it has constant composition and can be separated into several elements.
, SAMPLE EXERCISE 1.2 Using Metric Prefixes
What is the name given to the unit that equals (a) 10–9 gram, (b) 10–6 second, (c) 10–3 meter?
Solution In each case we can refer to Table 1.5, finding the prefix related to each of the decimal fractions: (a)
nanogram, ng, (b) microsecond, s (c) millimeter, mm.
PRACTICE EXERCISE
(a) What decimal fraction of a second is a picosecond, ps? (b) Express the measurement 6.0 103 m using a
prefix to replace the power of ten. (c) Use exponential notation to express 3.76 mg in grams.
Answers: (a) 10–12 second, (b) 6.0 km, (c) 3.76 10–3 g
