Download Chapter 3 Reading Questions

Chapter 3 Reading Questions
1. What type of question could you answer with a knowledge of stoichiometry?
a. How much material will a polymerization reaction yield?
b. What amount of exhaust gases will a test of a fuel mixture produce?
c. What quantity of air pollutants will a sample release when burned?
d. All of the above could be answered with a knowledge of stiochiometry
2. How do chemists count atoms, ions, molecules, and formula units?
a. They use a microscope
b. They use an abacus
c. Weigh them
d. All of the above
3. A mole is defined as
a. the amount of substance that contains the same number of entities as there are
atoms in exactly 12 g of carbon-12
b. the amount of substance that contains the same number of entities as there are
atoms in exactly 14 g of carbon-14
c. the amount of substance that contains the same number of entities as there are
atoms in exactly 16 g of oxygen-16
d. the amount of substance that contains the same number of entities as there are
atoms in exactly 1 g of hydrogen-1
4. Avogadro’s number is equal to
a. 6.022 x 1010 entities
b. 6.022 x 1023 entities
c. 6.022 x 1015 entities
d. 6.022 x 1033 entities
5. The central relationship between the mass of one atom and the mass of 1 mole of
those atoms is that
a. the atomic mass of an element expressed in amu is numerically the same as the
mass of 1 mole of atoms of the element expressed in grams
b. the atomic mass of an element expressed in amu is numerically the same as the
mass of 100 moles of atoms of the element expressed in grams
c. the atomic mass of an element expressed in amu is numerically the same as the
mass of 1 mole of atoms of the element expressed in kilograms
d. the atomic mass of an element expressed in amu is numerically the same as the
mass of 1000 mole of atoms of the element expressed in grams
6. The molecular mass (or formula mass) of a compound expressed in amu is
a. numerically the same as the mass of 10 mole of the compound expressed in
grams
b. numerically the same as the mass of 100 mole of the compound expressed in
grams
c. numerically the same as the mass of 1000 mole of the compound expressed in
grams
d. numerically the same as the mass of 1 mole of the compound expressed in
grams
7. The molar mass of a substance is the
a. mass per mole of its entities (atoms, molecules, or formula units)
b. mass per kilogram of its entities (atoms, molecules, or formula units)
c. mass per liter of its entities (atoms, molecules, or formula units)
d. all of the above are correct answers
8. You find the molar mass of an element by
a. looking up its atomic number in the periodic table
b. looking up its atomic mass in the periodic table
c. looking up its group number in the periodic table
d. all of the above are correct answers
9. For monatomic elements, the molar mass is the numerical value of
a. the atomic number expressed in moles/liter
b. the atomic mass expressed in moles/kilogram
c. the atomic mass expressed in grams/mole
d. all of the above are correct answers
10. To determine the molar mass of oxygen, you would
a. multiply the atomic mass of oxygen by two and express it in grams/mole
b. multiply the atomic mass of oxygen by eight and express it in grams/mole
c. multiply the atomic mass of oxygen by three and express it in grams/mole
d. multiply the atomic mass of oxygen by four and express it in grams/mole
11. The molar mass of a compound is the
a. product of the atomic numbers of the atoms of the elements in the formula
b. sum of the atomic numbers of the atoms of the elements in the formula
c. sum of the molar masses of the atoms of the elements in the formula
d. product of the molar masses of the atoms of the elements in the formula
12. The simplest whole-number ratio of moles of each element in a compound is the
a. molecular formula
b. empirical formula
c. atomic mass
d. molar mass
13. The actual number of moles of each element in 1 mol of compound is the
a. molecular formula
b. empirical formula
c. atomic mass
d. molar mass
14. A method used to measure the amounts of carbon and hydrogen in a combustible
organic compound is
a. distillation
b. filtration
c. crystallization
d. combustion analysis
15. Chemical formulas represent
a. real two-dimensional objects
b. real three-dimensional objects
c. the number of protons in a molecule
d. the number of electrons in a molecule
16. Which of the following statements concerning empirical formulas is TRUE?
a. Empirical formulas tell the relative number of each type of atom
b. Empirical formulas tells nothing about molecular structure
c. Different compounds can have the same empirical formula
d. All of the above statements are true
17. Isomers are compounds with
a. different molecular formulas but similar properties
b. the same molecular formula but different properties
c. different molecular formulas and similar properties
d. the same molecular formula and same properties
18. The simplest type of isomerism is called
a. structural isomerism and occurs when atoms link together in different
arrangement
b. structural isomerism and occurs when atoms link together in the same
arrangement
c. polymer isomerism and occurs when atoms link together in different
arrangement
d. polymer isomerism and occurs when atoms link together in the same
arrangement
19. Which of the following statements is TRUE?
a. As the number and kinds of atoms increase, the number of isomers – that is,
the number of structural formulas that can be written for a given molecular
formula – decreases
b. As the number and kinds of atoms increase, the number of isomers – that is,
the number of structural formulas that can be written for a given molecular
formula – also increases
c. As the number and kinds of atoms decrease, the number of isomers – that is,
the number of structural formulas that can be written for a given molecular
formula – also increases
d. None of the above statements are true
20. The most important reason for thinking in terms of moles is because it
a. clarifies the amount of substances taking part in a reaction
b. clarifies the states of matter in a chemical reaction
c. clarifies the empirical formulas in a chemical reaction
d. all of the above are correct answers
21. A chemical equation is a
a. statement in formulas that expresses the identities and quantities of the
substances involved in a chemical or physical change
b. statement in formulas that only expresses the identities of the substances
involved in a chemical or physical change
c. statement in formulas that only expresses the identities and quantities of the
substances involved in chemical changes only
d. statement in formulas that expresses the identities and quantities of the
substances involved in physical changes only
22. For a chemical equation to be accurate, it must
a. be balanced
b. have the same number of each atom of both sides of the equation
c. follow the law of conservation of mass
d. all of the above are correct
23. Which of the following statements is NOT true about a chemical equation?
a. All the substances that react during a chemical change, called the reactants, are
placed to the left of yield arrow
b. All of the substances produced, called the products, are placed to the right of
the yield arrow
c. All the substances that react during a chemical change, called the products, are
placed to the left of yield arrow
d. All of the above statements are correct statements about chemical equations
24. A balancing coefficient is a
a. numerical multiplier of all the atoms in the formula that follows it.
b. numerical change in the formula subscripts
c. numerical change in the charge of an ion
d. all of the above are correct
25. Which of the following is NOT true about balancing equations?
a. A coefficient operates on all atoms in the formula that follows it
b. In balancing an equation, chemical formulas can be altered
c. You cannot add other reactants or products to balance the equation
d. We balance an equation with the smallest whole-number coefficients
26. In balancing equations, which of the following statements is NOT correct?
a. The number of moles of one substance is stoichiometrically equivalent to the
number of moles of any other substance
b. The term stoichiometrically equivalent means that a definite amount of one
substance is formed from, produces, or reacts with a definite amount of
another
c. The quantitative relationships expressed as stoichiometrically equivalent molar
ratios are used as conversion factors
d. All of the above statements are TRUE
27. The limiting reactant
a. is the one there is not enough of
b. is the reactant that limits the amount of the other reactant that can react
c. is the reactant that yields the lower amount of product
d. all of the above are correct
28. Which of the following is NOT true about the theoretical yield?
a. It is the amount indicated by the stoichiometrically equivalent molar ratio in
the balanced equation
b. The theoretical yield is always obtained
c. The theoretical yield is never obtained
d. The theoretical yield obtained is largely uncontrollable
29. Which of the following statements is NOT true?
a. The amount that you actually obtain in a chemical reaction is the actual yield.
b. The percent yield is the actual yield expressed as a percentage of the
theoretical yield
c. Percent yield is always equal to 100%
d. Percent yield is always less than 100%
30. Which of the following statements about green chemistry is NOT true?
a. The purpose of green chemistry is to develop methods that reduce or prevent
the release of harmful substances into the environment
b. Green chemist take into consideration the quantity of energy needed
c. Green chemist take into consideration the nature of the solvents required
d. Green chemist are not concerned about atom economy
31. Which of the following is NOT true concerning solution stoichiometry?
a. Concentration refers to the number of kilograms present in a certain volume of
solution
b. You must know the concentration to find the volume that contains a given
number of moles
c. Of the various ways to express concentration, the most important is molarity
d. Concentration refers to the number of moles present in a certain volume of
solution
32. Which of the following statements is NOT true?
a. A typical solution consists of a smaller amount of one substance, the solute,
dissolved in a larger amount of another substance, the solvent.
b. The concentration of a solution is usually expressed as the amount of solute
dissolved in a given amount of solution.
c. Concentration is an extensive property
d. Molarity expresses the concentration in units of moles of solute per liter of
solution