Mixed Exercises
*59.A sample is marked as containing 22.8% calcium carbon-
ate by mass. (a) How many grams of calcium carbonate are
contained in 64.33 g of the sample? (b) How many grams
of the sample would contain 11.4 g of calcium carbonate?
*60.An iron ore is found to contain 9.24% hematite (a com-
pound that contains iron). (a) How many tons of this ore
would contain 8.40 tons of hematite? (b) How many kilo-
grams of this ore would contain 9.40 kg of hematite?
*61.A foundry releases 6.0 tons of gas into the atmosphere each
day. The gas contains 2.2% sulfur dioxide by mass. What
mass of sulfur dioxide is released in a five-day week?
*62.A certain chemical process requires 215 gal of pure water
each day. The available water contains 11 parts per million
(ppm) by mass of salt (i.e., for every 1,000,000 parts of
available water, 11 parts of salt). What mass of salt must
be removed each day? A gallon of water weighs 3.67 kg.
*63.The radius of a hydrogen atom is about 0.37 Å, and the
average radius of the earth’s orbit around the sun is about
1.5 108 km. Find the ratio of the average radius of the
earth’s orbit to the radius of the hydrogen atom.
*64.A notice on a bridge informs drivers that the height of
the bridge is 26.5 ft. How tall in meters is an 18-wheel
tractor-trailer combination if it just touches the bridge?
*65.Some American car manufacturers install speedometers
that indicate speed in the English system and in the met-
ric system (mi/h and km/h). What is the metric speed if
the car is traveling at 65 mi/h?
*66.The lethal dose of potassium cyanide (KCN) taken orally
is 1.6 mg/kg of body weight. Calculate the lethal dose of
potassium cyanide taken orally by a 175-lb person.
*67.Suppose you ran a mile in 4.00 min. (a) What would be
your average speed in km/h? (b) What would be your av-
erage speed in cm/s? (c) What would be your time (in min-
utes:seconds) for 1500 m?
*68.The distance light travels through space in one year is
called one light-year. Using the speed of light in a vacuum(listed in Appendix D), and assuming that one year is 365
days, determine the distance of a light-year in kilometers
and in miles.CONCEPTUAL EXERCISES*69.If you were given the job of choosing the materials from
which pots and pans were to be made, what kinds of
materials would you choose on the basis of specific heat?
Why?
*70.Fill a kitchen pan half-full with water. Place the pan on an
active burner. Place one finger on the edge of the pan and
one just in the water. Which finger will feel the heat first?
Explain your answer.
*71.Which is more dense at 0°C, ice or water? How do you
know?
*72.Which has the higher temperature, a sample of water at
65°C or a sample of iron at 65°F?
*73.The drawing in the circle (below) is a greatly expanded
representation of the molecules in the liquid of the
thermometer on the left. The thermometer registers
20°C. Which of the figures (a–d) is the best representation
of the liquid in this same thermometer at 10°C? (Assume
that the same volume of liquid is shown in each expanded
representation.)44 CHAPTER 1: The Foundations of Chemistry
0 ̊10 ̊20 ̊30 ̊0 ̊10 ̊20 ̊30 ̊(a) (b) (c) (d)
Exercise 73