1.E: Matter and Measurement (Exercises)
 Page ID
 43464
These are homework exercises to accompany the Textmap created for "Chemistry: The Central Science" by Brown et al. Complementary General Chemistry question banks can be found for other Textmaps and can be accessed here. In addition to these publicly available questions, access to private problems bank for use in exams and homework is available to faculty only on an individual basis; please contact Delmar Larsen for an account with access permission.
1.2
CONCEPTUAL PROBLEMS
Please be sure you are familiar with the topics discussed in Essential Skills 1 (Section 1.9) before proceeding to the Conceptual Problems.

What is the difference between mass and weight? Is the mass of an object on Earth the same as the mass of the same object on Jupiter? Why or why not?

Is it accurate to say that a substance with a mass of 1 kg weighs 2.2 lb? Why or why not?

What factor must be considered when reporting the weight of an object as opposed to its mass?

Construct a table with the headings “Solid,” “Liquid,” and “Gas.” For any given substance, state what you expect for each of the following:
 the relative densities of the three phases
 the physical shapes of the three phases
 the volumes for the same mass of compound
 the sensitivity of the volume of each phase to changes in temperature
 the sensitivity of the volume to changes in pressure

Classify each substance as homogeneous or heterogeneous and explain your reasoning.
 platinum
 a carbonated beverage
 bronze
 wood
 natural gas
 Styrofoam

Classify each substance as homogeneous or heterogeneous and explain your reasoning.
 snowflakes
 gasoline
 black tea
 plastic wrap
 blood
 water containing ice cubes

Classify each substance as a pure substance or a mixture and explain your reasoning.
 seawater
 coffee
 14karat gold
 diamond
 distilled water

Classify each substance as a pure substance or a mixture.
 cardboard
 caffeine
 tin
 a vitamin tablet
 helium gas

Classify each substance as an element or a compound.
 sugar
 silver
 rust
 rubbing alcohol
 copper

Classify each substance as an element or a compound.
 water
 iron
 hydrogen gas
 glass
 nylon

What techniques could be used to separate each of the following?
 sugar and water from an aqueous solution of sugar
 a mixture of sugar and sand
 a heterogeneous mixture of solids with different solubilities

What techniques could be used to separate each of the following?
 solid calcium chloride from a solution of calcium chloride in water
 the components of a solution of vinegar in water
 particulates from water in a fish tank

Match each separation technique in (a) with the physical/chemical property that each takes advantage of in (b).
 crystallization, distillation, filtration
 volatility, physical state, solubility

The following figures illustrate the arrangement of atoms in some samples of matter. Which figures are related by a physical change? By a chemical change?

Classify each statement as an extensive property or an intensive property.
 Carbon, in the form of diamond, is one of the hardest known materials.
 A sample of crystalline silicon, a grayish solid, has a mass of 14.3 g.
 Germanium has a density of 5.32 g/cm3.
 Gray tin converts to white tin at 13.2°C.
 Lead is a bluishwhite metal.

Classify each statement as a physical property or a chemical property.
 Fluorine etches glass.
 Chlorine interacts with moisture in the lungs to produce a respiratory irritant.
 Bromine is a reddishbrown liquid.
 Iodine has a density of 11.27 g/L at 0°C.
NUMERICAL PROBLEMS
Please be sure you are familiar with the topics discussed in Essential Skills 1 (Section 1.9) before proceeding to the Numerical Problems.

If a person weighs 176 lb on Earth, what is his or her mass on Mars, where the force of gravity is 37% of that on Earth?

If a person weighs 135 lb on Earth, what is his or her mass on Jupiter, where the force of gravity is 236% of that on Earth?

Calculate the volume of 10.00 g of each element and then arrange the elements in order of decreasing volume. The numbers in parentheses are densities.
 copper (8.92 g/cm3)
 calcium (1.54 g/cm3)
 titanium (4.51 g/cm3)
 iridium (22.85 g/cm3)

Given 15.00 g of each element, calculate the volume of each and then arrange the elements in order of increasing volume. The numbers in parentheses are densities.
 gold (19.32 g/cm3)
 lead (11.34 g/cm3)
 iron (7.87 g/cm3)
 sulfur (2.07 g/cm3)

A silver bar has dimensions of 10.00 cm × 4.00 cm × 1.50 cm, and the density of silver is 10.49 g/cm3. What is the mass of the bar?

Platinum has a density of 21.45 g/cm3. What is the mass of a platinum bar measuring 3.00 cm × 1.50 cm × 0.500 cm?

Complete the following table.
Density (g/cm3) Mass (g) Volume (cm3) Element 3.14 79.904 Br 3.51 3.42 C 39.1 45.5 K 11.34 207.2 Pb 107.868 10.28 Ag 6.51 14.0 Zr 
Gold has a density of 19.30 g/cm3. If a person who weighs 85.00 kg (1 kg = 1000 g) were given his or her weight in gold, what volume (in cm3) would the gold occupy? Are we justified in using the SI unit of mass for the person’s weight in this case?

An irregularly shaped piece of magnesium with a mass of 11.81 g was dropped into a graduated cylinder partially filled with water. The magnesium displaced 6.80 mL of water. What is the density of magnesium?

The density of copper is 8.92 g/cm3. If a 10.00 g sample is placed in a graduated cylinder that contains 15.0 mL of water, what is the total volume that would be occupied?

At 20°C, the density of fresh water is 0.9982 kg/m3, and the density of seawater is 1.025 kg/m3. Will a ship float higher in fresh water or in seawater? Explain your reasoning.
ANSWERS
1. Unlike weight, mass does not depend on location. The mass of the person is therefore the same on Earth and Mars: 176 lb ÷ 2.2 lb/kg = 80 kg.
3.
a. Cu: 1.12 cm^{3}
b. Ca: 6.49 cm^{3}
c. Ti: 2.22 cm^{3}
d. Ir: 0.4376 cm^{3}
Volume decreases: Ca > Ti > Cu > Ir
5. 629 g
1.3 Problems
 Chemical Change
 Physical Change
 Chemical Property
 Physical Property
 None of the above
 Chemical Change, Physical Change
 Physical Change, Chemical Change
 Chemical Property, Physical Change
 Physical Property, Chemical Change
 None of the above
 Chemical Change
 Physical Change
 Chemical Property
 Physical Property
 None of the above
 Chemical Change
 Physical Change
 Chemical Property
 Physical Property
 None of the above
5. Which of the following are examples of matter?
 A Dog
 Carbon Dioxide
 Ice Cubes
 copper (II) nitrate
 A Moving Car
6. The formation of gas bubbles is a sign of what type of change?
1.3 Solutions
1)chemical change 2) chemical property, physical change 3) physical change 4) physical property 5) All of the above 6) chemical 7) False 8) True 9) No 10) physical property
1.6
 Write a single equation to show how to convert
 \(cm/min\) to \(km/h\);
 \(cal/oz\) to \(J/g\)
 \(lb/in^2\) to \(kg/m^2\) and
 \(°C/s\) to \(K/h\).
 How many Calories are contained in an 8.0 oz serving of green beans if their fuel value is 1.5 kJ/g?
 Gasoline has a fuel value of 48 kJ/g. How much energy in joules can be obtained by filling an automobile’s 16.3 gal tank with gasoline, assuming gasoline has a density of 0.70 g/mL?
Solutions
 Converting from one compound unit to another
 \[\left(\dfrac{\cancel{cm}}{\cancel{min}}\right)\left(\dfrac{1\;\cancel{m}}{100\; \cancel{cm}}\right)\left(\dfrac{1\; km}{1000\;\cancel{m}}\right)\left(\dfrac{60\;\cancel{min}}{1\; h}\right)= km/h\]
 \[\left(\dfrac{\cancel{cal}}{\cancel{oz}}\right) \left(\dfrac{4.184 \;J}{1\; \cancel{cal}}\right) \left( \dfrac{16\; \cancel{oz}}{1\; \cancel{lb}}\right) \left(\dfrac{1\; \cancel{lb}}{453.59 \;g}\right)= J/g \]
 \[\left(\dfrac{\cancel{lb}}{\cancel{in^2}}\right)\left(\dfrac{16 \;\cancel{oz}}{\cancel{lb}}\right) \left(\dfrac{28.35\; \cancel{g}}{\cancel{oz}}\right)\left(\dfrac{1\; kg}{1000\; \cancel{g}}\right) \left[\dfrac{(36\; \cancel{in.})^2}{(1\;\cancel{yd})^2}\right] \left[\dfrac{1.09 \;\cancel{yd^2}}{1 \;m^2}\right] =kg/m^2\]
 \[\left(\dfrac{°C}{\cancel{s}}\right)\left(\dfrac{60\;\cancel{s}}{1\;\cancel{min}}\right)\left(\dfrac{60\;\cancel{min}}{h}\right)+273.15 K = K/h\]
 Our goal is to convert 1.5 kJ/g to Calories in 8 oz:\[\left(\dfrac{1.5 \; \cancel{kJ}}{1\; \cancel{g}}\right)\left(\dfrac{1000\; \cancel{J}}{1\; \cancel{kJ}}\right)\left(\dfrac{1\; \cancel{cal}}{4.184\; \cancel{J}}\right)\left(\dfrac{1\; Cal}{1000\; \cancel{cal}}\right)\left(\dfrac{28.35 \;\cancel{g}}{1\; \cancel{oz}}\right)\left(8.0\; \cancel{oz}\right)= 81\; Cal\]
 Our goal is to use the energy content, 48 kJ/g, and the density, 0.70 g/mL, to obtain the number of joules in 16.3 gal of gasoline: \[\left(\dfrac{48\; \cancel{kJ}}{g}\right)\left(\dfrac{1000\; J}{\cancel{kJ}}\right)\left(\dfrac{0.70\; \cancel{g}}{\cancel{mL}}\right)\left(\dfrac{1000\; \cancel{mL}}{\cancel{L}}\right)\left(\dfrac{3.79 \;\cancel{L}}{\cancel{gal}}\right)\left(16.3 \;\cancel{gal}\right)= 2.1 \times 10^9 J\]