← All sample quizzes

Sample Quiz: Chemistry Chapter 1

Introduction: Matter, Energy, and Measurement — Chemistry: The Central Science, 15th Global Edition in SI Units (Theodore L. Brown, H. Eugene LeMay, Jr., Bruce E. Bursten, Catherine J. Murphy, Patrick M. Woodward, Matthew W. Stoltzfus)

10 questions · 23 points · answer key included

Download the Word file

No account, no email — the file downloads straight away.

Multiple Choice

  1. According to the law of constant composition, if aspirin is composed of 60.0% carbon, 4.5% hydrogen, and 35.5% oxygen by mass, what can be concluded about aspirin samples from different sources? (2 PTS)
    1. Aspirin from different sources will have different elemental compositions depending on where it was synthesized.
    2. Natural aspirin will have a different composition than laboratory-synthesized aspirin.
    3. The percentages apply only to aspirin extracted from willow bark, not synthetic aspirin.
    4. All aspirin samples, regardless of source, will have the same elemental composition and properties.
  2. White gold contains gold and a white metal such as palladium. Two samples of white gold differ in the relative amounts of gold and palladium they contain, but both samples are uniform in composition throughout. How should white gold be classified? (2 PTS)
    1. A pure substance and an element
    2. A mixture and specifically a heterogeneous mixture
    3. A pure substance and a compound
    4. A mixture and specifically a homogeneous mixture
  3. Water can be decomposed into hydrogen and oxygen gases by passing an electrical current through it. This decomposition shows that water contains 11% hydrogen and 89% oxygen by mass. Why does water appear to be mostly oxygen by mass even though each water molecule contains two hydrogen atoms and only one oxygen atom? (2 PTS)
    1. The electrical current used in decomposition preferentially breaks bonds to hydrogen atoms.
    2. Oxygen atoms are much larger than hydrogen atoms, so they occupy more space in the molecule.
    3. Oxygen is more abundant in Earth's atmosphere, so it comprises more of water's mass.
    4. Hydrogen atoms are much lighter than oxygen atoms, so two hydrogen atoms weigh less than one oxygen atom.
  4. Energy is defined as the capacity to do work or transfer heat. According to the textbook, work is calculated using the formula w = F × d. In this formula, what do the variables F and d represent? (2 PTS)
    1. F is force and d is distance
    2. F is frequency and d is distance
    3. F is force and d is density
    4. F is frequency and d is density
  5. A student measures the mass of six jelly beans and obtains values of 3.15, 3.12, 2.98, 3.14, 3.02, and 3.09 g. The jar with all the beans has a mass of 2082 g, and the empty jar has a mass of 653 g. Based on these measurements, approximately how many jelly beans are in the jar? (2 PTS)
    1. Approximately 420 beans
    2. Approximately 510 beans
    3. Approximately 480 beans
    4. Approximately 450 beans

True or False

  1. According to the law of constant composition, a compound prepared in a laboratory will have a different elemental composition than the same compound found in nature. (1 PTS)
  2. Elements are substances that cannot be decomposed into simpler substances, and on the molecular level, each element is composed of only one kind of atom. (1 PTS)
  3. When water boils in a pot and bubbles of water vapor rise through the liquid, this represents a chemical change. (1 PTS)

Problem Solving

  1. A student needs to determine the density of a liquid sample. The student measures the mass of an empty graduated cylinder as 45.3 g. After adding the liquid, the total mass is 127.8 g, and the volume of liquid is 82.5 mL. Calculate the density of the liquid in g/mL and explain how many significant figures should be reported in the final answer. (5 PTS)
  2. A tricycle driver in Manila carries a cargo of rice in sacks. The driver measures the mass of an empty sack as 0.85 kg. After filling the sack with rice, the total mass is 48.6 kg. The rice has a density of 0.75 g/cm3. Calculate (a) the mass of rice in the sack in grams, and (b) the volume of rice in the sack in liters. Show all your work and express your final answers with appropriate significant figures. (5 PTS)

Answer key

Multiple Choice

  1. 1.D — The law of constant composition states that a pure compound has the same composition and properties regardless of its source, whether from nature or a laboratory.
  2. 2.D — White gold is a mixture because it contains two different elements (gold and palladium) in varying proportions. It is homogeneous because it is uniform in composition throughout.
  3. 3.D — Although water molecules contain two hydrogen atoms and one oxygen atom, hydrogen atoms are much lighter than oxygen atoms, so the two hydrogen atoms together weigh less than the single oxygen atom, resulting in oxygen comprising 89% of water's mass.
  4. 4.A — The formula w = F × d defines work as the product of force (F) exerted on an object and the distance (d) that it moves.
  5. 5.D — The average mass of one bean is (3.15 + 3.12 + 2.98 + 3.14 + 3.02 + 3.09) / 6 = 3.08 g. The mass of beans in the jar is 2082 - 653 = 1429 g. The number of beans is 1429 / 3.08 ≈ 464, which rounds to approximately 450 beans given the precision of the measurements.

True or False

  1. 1.False — The law of constant composition states that a pure compound has the same composition and properties regardless of whether it is prepared in a laboratory or found in nature.
  2. 2.True — This is the definition of an element provided in the textbook: elements are substances that cannot be decomposed into simpler substances, and each element is composed of only one kind of atom.
  3. 3.False — Boiling water to produce water vapor is a physical change because the water molecules remain the same; only the physical state changes from liquid to gas.

Problem Solving

  1. 1.The mass of the liquid is 127.8 - 45.3 = 82.5 g. Using the formula Density = mass/volume, we have Density = 82.5 g / 82.5 mL = 1.00 g/mL. The answer should be reported with three significant figures (1.00 g/mL) because the volume measurement (82.5 mL) has three significant figures, which is the limiting factor in the calculation. — This problem requires calculating density using the formula density = mass/volume, determining significant figures based on the measurement with the fewest significant figures, and understanding that the volume measurement limits the precision of the final answer.
  2. 2.(a) Mass of rice = 48.6 kg - 0.85 kg = 47.75 kg = 47,750 g ≈ 47,800 g (to 3 sig figs). (b) Using the formula Volume = mass/density, we have Volume = 47,750 g / 0.75 g/cm3 = 63,667 cm3 ≈ 64,000 cm3 (to 2 sig figs). Converting to liters: 64,000 cm3 × (1 mL / 1 cm3) × (1 L / 1000 mL) = 64 L. The final answer should be reported as 64 L because the density (0.75 g/cm3) has only 2 significant figures. — This problem requires unit conversion from kg to g, application of the density formula to find volume, conversion from cm3 to liters, and careful attention to significant figures based on the measurement with the fewest significant figures.