When gaseous elements combine:
a. infinite amounts of each gas can combine in the same space because gases are not matter.
b. very precise ratios of each gas combine to form gaseous compounds.
c. gases only combine as mixtures, not as compounds.
d. most cannot form compounds because they are already in the form of diatomic (i.e. two-atom) molecules.
e. they form compounds with unpredictable ratios of each element.
[Ques. 2] The bolt and nut model shown in this figure represents all but which of the pairs of molecules?
a. CO and CO2
b. H2 and H2O
c. NO and NO2
[Ques. 3] The concept of molecules:
a. helps model how the law of definite proportions might work.
b. proves the law of definite proportions.
c. is unrelated to the law of definite proportions.
d. violates the law of definite proportions.
e. supports the Aristotelian concept of four basic elements.
[Ques. 4] What is the law of definite proportions?
a. All compounds have half as much of one element as they do of the other element in the compound.
b. Each chemical compound always contains the same elements in the same proportion by mass.
c. In any given compound, the ratio of the number of atoms of can vary from molecule to molecule.
d. All compounds have equal amounts of each element that composes them.
e. In any given compound, the ratios of the mass of the elements can vary widely.
[Ques. 5] Compounds:
a. always have the same major characteristics as their component elements.
b. never have the same major characteristics as any of their component elements.
c. often consist of a single element.
d. are often surprisingly different from their component elements.
e. have characteristics that can be easily predicted if you know the component elements.
[Ques. 6] What observation first led scientists to conclude that water was a compound, not an element?
a. Iron objects rust more readily in the presence of water.
b. Water is effective in putting out fires.
c. Water could be broken apart into hydrogen and oxygen by electrolysis.
d. Water is formed when hydrogen burns.
e. Water is one of the most abundant substances on Earth.
[Ques. 7] The electrolysis of water breaks up the water molecules into hydrogen and oxygen, as shown in this photo. Why is the volume of the hydrogen that is collected twice the volume of the oxygen collected?
a. Hydrogen atoms are twice as big as oxygen atoms.
b. There are twice as many hydrogen atoms in water as there are oxygen atoms.
c. Oxygen atoms are 16 times as massive as hydrogen atoms.
d. A gas formed from oxygen gas particles takes up twice as much space as a gas formed from the same number of hydrogen gas particles under identical conditions.
e. The hydrogen occurs as H2 molecules of two atoms each while the oxygen is just single O atoms.
[Ques. 8] Which of these is NOT true about the early Arab practice of alchemy?
a. Alchemists were looking for the secrets of eternal life and how to turn inexpensive materials into gold.
b. Alchemists were early experimental scientists and observers.
c. Alchemy was pseudoscience, rather than involving any form of research.
d. Alchemists were important predecessors of modern chemists.
e. Alchemists studied materials and how they changed.
[Ques. 9] Which of these things is NOT a model in the sense used in the textbook?
a. Someone who is employed to appear in advertisements of merchandise.
b. A guess about the contents of a box based on the weight of the box and the sounds it makes when shaken.
c. A mathematical equation describing an observation of an unknown process.
d. An analogy to a known process or object.
e. A theory of what your cousin might have put in a box she sent you for your birthday.
[Ques. 10] Microscopic properties of an object:
a. are just small versions of the macroscopic properties.
b. are completely unrelated to macroscopic properties.
c. are overall large scale properties.
d. are the properties of particles that make up the object.
e. are the average of many properties of individual particles.
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