Chapter 1: Essential Ideas

Chapter 1 Practice

1.1 Chemistry in Context: The Scientific Method [Go to section 1.1]

  1. Explain how you could experimentally determine whether the outside temperature is higher or lower than 0 °C (32 °F) without using a thermometer.
  2. Identify each of the following statements as being most similar to a hypothesis, a law, or a theory. Explain your reasoning.
    1. Falling barometric pressure precedes the onset of bad weather.
    2. All life on earth has evolved from a common, primitive organism through the process of natural selection.
    3. My truck’s gas mileage has dropped significantly, probably because it’s due for a tune-up.
  3. The amount of heat required to melt 2 lbs of ice is twice the amount of heat required to melt 1 lb of ice. Is this observation a macroscopic or microscopic description of chemical behavior? Explain your answer.
  4. According to one theory, the pressure of a gas increases as its volume decreases, because the molecules in the gas have to move a shorter distance to hit the walls of the container. Does this theory follow a macroscopic or microscopic description of chemical behavior? Explain your answer.
Show Selected Solutions
  1. Place a glass of water outside. It will freeze if the temperature is below 0 °C.
  2. Macroscopic. The heat required is determined from macroscopic properties.


1.2 Phases and Classification of Matter [Go to section 1.2]

  1. What properties distinguish solids from liquids? Liquids from gases? Solids from gases?
  2. Why do we use an object’s mass, rather than its weight, to indicate the amount of matter it contains?
  3. Many of the items you purchase are mixtures of pure compounds. Select three of these commercial products and prepare a list of the ingredients that are pure compounds.  
  4. How does a heterogeneous mixture differ from a homogeneous mixture? How are they similar?
  5. How are the molecules in oxygen gas, the molecules in hydrogen gas, and water molecules similar? How do they differ?
  6. A sulfur atom and a sulfur molecule are not identical. What is the difference?
  7. As we drive an automobile, we don’t think about the chemicals consumed and produced. Prepare a list of the principal chemicals consumed and produced during the operation of an automobile.
  8. Classify each of the following as an element, a compound, or a mixture:
    1. nitrogen
    2. sulfur
    3. carbon dioxide
    4. air
    5. a substance composed of molecules each of which contains one hydrogen atom and one chlorine atom
    6. a substance composed of molecules each of which contains two iodine atoms
    7. baking soda
    8. sucrose
    9. baking powder
    10. gasoline
  9. Yeast converts glucose to ethanol and carbon dioxide during anaerobic fermentation as depicted in the simple chemical equation below:

    [latex]\text{glucose} \longrightarrow \text{ethanol + carbon dioxide}[/latex]

    1. If 200.0 g of glucose is fully converted, what will be the total mass of ethanol and carbon dioxide produced?
    2. If the fermentation is carried out in an open container, would you expect the mass of the container and contents after fermentation to be less than, greater than, or the same as the mass of the container and contents before fermentation? Explain.
    3. If 97.7 g of carbon dioxide is produced, what mass of ethanol is produced?
  10. Matter is everywhere around us. Make a list by name of fifteen different kinds of matter that you encounter every day. Your list should include (and label at least one example of each) the following: a solid, a liquid, a gas, an element, a compound, a homogenous mixture, a heterogeneous mixture, and a pure substance.
  11. We refer to astronauts in space as weightless, but not without mass. Why?
  12. As stated in the text, convincing examples that demonstrate the law of conservation of matter outside of the laboratory are few and far between. Indicate whether the mass would increase, decrease, or stay the same for the following scenarios where chemical reactions take place:
    1. Exactly one pound of bread dough is placed in a baking tin. The dough is cooked in an oven at 350 °F releasing a wonderful aroma of freshly baked bread during the cooking process. Is the mass of the baked loaf less than, greater than, or the same as the one pound of original dough? Explain.
    2. When magnesium burns in air a white flaky ash of magnesium oxide is produced. Is the mass of magnesium oxide less than, greater than, or the same as the original piece of magnesium? Explain.
    3. Antoine Lavoisier, the French scientist credited with first stating the law of conservation of matter, heated a mixture of tin and air in a sealed flask to produce tin oxide. Did the mass of the sealed flask and contents decrease, increase, or remain the same after the heating?
Show Selected Solutions
  1. Liquids can change their shape (flow); solids can’t. Gases can undergo large volume changes as pressure changes; liquids do not. Gases flow and change volume; solids do not.
  2. Answers will vary. Sample answer: Gatorade contains water, sugar, dextrose, citric acid, salt, sodium chloride, monopotassium phosphate, and sucrose acetate isobutyrate.
  3. In each case, a molecule consists of two or more combined atoms. They differ in that the types of atoms change from one substance to the next.
  4. Gasoline (a mixture of compounds), oxygen, and to a lesser extent, nitrogen are consumed. Carbon dioxide and water are the principal products. Carbon monoxide and nitrogen oxides are produced in lesser amounts.
  5. The answers are as follows:
    1. 200.0 g
    2. The mass of the container and contents would decrease as carbon dioxide is a gaseous product and would leave the container.
    3. 102.3 g
  6. Mass is a measurement of the amount of matter in an object. Weight is the force exerted on the object by gravity. The astronaut’s mass does not change, even when they are not experiencing the force of gravity.

1.3 Physical and Chemical Properties [Go to section 1.3]

  1. Explain the difference between extensive properties and intensive properties.
  2. Classify the six underlined properties in the following paragraph as chemical or physical:
    1. Fluorine is a pale yellow gas that reacts with most substances. The free element melts at –220 °C and boils at –188 °C. Finely divided metals burn in fluorine with a bright flame. Nineteen grams of fluorine will react with 1.0 gram of hydrogen.
  3. The density (d) of a substance is an intensive property that is defined as the ratio of its mass (m) to its volume (V).

    [latex]\text{density = }\frac{\text{mass}}{\text{volume}}\qquad[/latex] [latex]\text{d = }\frac{\text{m}}{\text{V}}[/latex]

    Considering that mass and volume are both extensive properties, explain why their ratio, density, is intensive.

  4. Classify each of the following changes as physical or chemical:
    1. coal burning
    2. ice melting
    3. mixing chocolate syrup with milk
    4. explosion of a firecracker
    5. magnetizing of a screwdriver
  5. A 2.0-liter volume of hydrogen gas combined with 1.0 liter of oxygen gas to produce 2.0 liters of water vapor. Does oxygen undergo a chemical or physical change?
Show Selected Solutions
  1. The value of an extensive property depends upon the amount of matter being considered, whereas the value of an intensive property is the same regardless of the amount of matter being considered.
  2. Being extensive properties, both mass and volume are directly proportional to the amount of substance under study. Dividing one extensive property by another will in effect “cancel” this dependence on amount, yielding a ratio that is independent of amount (an intensive property).
  3. Chemical

1.4 Measurements [Go to section 1.4]

  1. Is one liter about an ounce, a pint, a quart, or a gallon?
  2. Is a meter about an inch, a foot, a yard, or a mile?
  3. Give the name and symbol of the prefixes used with SI units to indicate multiplication by the following exact quantities.
    1. 103
    2. 10-2
    3. 0.1
    4. 10-3
    5. 1,000,000
    6. 0.000001
  4. Indicate the SI base units or derived units that are appropriate for the following measurements:
    1. the length of a marathon race (26 miles 385 yards)
    2. the mass of an automobile
    3. the volume of a swimming pool
    4. the speed of an airplane
    5. the density of gold
    6. the area of a football field
    7. the maximum temperature at the South Pole on April 1, 1913
Show Selected Solutions
  1. Yard
  2. The answers are as follows:
    1. Meter (m)
    2. Kilogram (kg)
    3. Cubic meter (m3)
    4. Kilometers/second (km/s)
    5. Kilograms per cubic meter (kg/m3)
    6. Square meters (m2)
    7. Kelvin (K)

1.5 Measurement Uncertainty, Accuracy, and Precision [Go to section 1.5]

  1. Indicate whether each of the following can be determined exactly or must be measured with some degree of uncertainty:
    1. the number of eggs in a basket
    2. the mass of a dozen eggs
    3. the number of gallons of gasoline necessary to fill an automobile gas tank
    4. the number of cm in 2 m
    5. the mass of a textbook
    6. the time required to drive from San Francisco to Kansas City at an average speed of 53 mi/h
  2. How many significant figures are contained in each of the following measurements?
    1. 53 cm
    2. 2.05 × 108 m
    3. 86,002 J
    4. 9.740 × 104 m/s
    5. 10.0613 m3
    6. 0.17 g/mL
    7. 0.88400 s
  3. The following quantities were reported on the labels of commercial products. Determine the number of significant figures in each.
    1. 0.0055 g active ingredients
    2. 12 tablets
    3. 3% hydrogen peroxide
    4. 5.5 ounces
    5. 473 mL
    6. 1.75% bismuth
    7. 0.001% phosphoric acid
    8. 99.80% inert ingredients
Show Selected Solutions
  1. The answers are as follows:
    1. 2
    2. 3
    3. 5
    4. 4
    5. 6
    6. 2
    7. 5

1.6 Mathematical Treatment of Measurement Results [Go to section 1.6]

  1. The label on a soft drink bottle gives the volume in two units: 2.0 L and 67.6 fl oz. Use this information to derive a conversion factor between the English and metric units. How many significant figures can you justify in your conversion factor?
  2. The label on a box of cereal gives the mass of cereal in two units: 978 grams and 34.5 oz. Use this information to find a conversion factor between the English and metric units. How many significant figures can you justify in your conversion factor?
  3. How many milliliters of a soft drink are contained in a 12.0-oz can?
  4. A barrel of oil is exactly 42 gal. How many liters of oil are in a barrel?
  5. Many medical laboratory tests are run using 5.0 μL blood serum. What is this volume in milliliters?
  6. Milk is sold by the liter in many countries. What is the volume of exactly [latex]\frac{1}{2}[/latex] gal of milk in liters?
  7. Gasoline is sold by the liter in many countries. How many liters are required to fill a 12.0-gal gas tank?
  8. Calculate these volumes.
    1. What is the volume of 25 g iodine, density = 4.93 g/cm3?
    2. What is the volume of 3.28 g gaseous hydrogen, density = 0.089 g/L?
Show Selected Solutions
  1. 2
  2. 355 mL
  3. 5.0 x 10-3 mL
  4. 45.4 L

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Chemistry Fundamentals Copyright © by Dr. Julie Donnelly, Dr. Nicole Lapeyrouse, and Dr. Matthew Rex is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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