1. Classify the following: oxygen and sugar dissolved in water.
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A. They are a mixture of an element and compounds.
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B. They are a mixture of elements.
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C. They are a mixture of compounds
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D. They produce a new compound.
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E. These are all pure substances, and therefore they do not mix.
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2. How can one tell from a chemical formula whether a substance is an element or a compound?
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A. The chemical formula for a compound contains two or more different elements while the chemical
formula for an element only shows one type of atom.
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B. The chemical formula for a compound always contains two elements while the chemical formula for an
element is shorter.
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C. The chemical formula for a compound is simpler than the chemical formula for an element.
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D. The chemical formula for an element is made up of only one atom while the chemical formula
for a compound will always have more than one atom.
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E. The chemical formula for a compound contains two or more different types of atoms, indicating that it is a mixture of elements.
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3. Compounds will have the same electron group arrangement and molecular shape if all of their electron
groups are bonding groups with no lone pairs. For which of these compounds does the electron group arrangement and molecular shape match?
1. PI3
2. SiF4
3. BeCl2
4. H2O
5. BBr3
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A. 2, 3, and 5
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B. 1, 2, and 3
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C. 2, 3, and 4
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D. 3, 4, and 5
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E. 1, 2, and 5
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4. How many grams of sulfur dioxide (SO2) are found in a 3.50 L container at 100. °C and a pressure of 2.00 atm?
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A. 14.7 grams SO2
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B. 4.37 grams SO2
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C. 280 grams SO2
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D. 54.6 grams SO2
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E. 0.85 grams SO2
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5. For many years alchemists tried to convert lead to gold. All of the following reasons for their failure are true EXCEPT
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A. To change lead into gold, alchemists needed to remove three protons from the nucleus of lead.
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B. Alchemists were not able to "cook" the reaction hot enough to provide the energy required to remove protons
from the lead nucleus. The energy required to overcome the lead atom's binding energy is enormous compared to the amount supplied by alchemist's "cooking".
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C. Alchemists did not know then that it is impossible to add or remove particles from the nucleus of an atom.
D. Alchemists were conducting ordinary chemical reactions, which only involve valence electrons and
not the nucleus. In chemical reactions atoms can change partners but not change their elemental identity
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E. Reacting lead carbonate with acid, alchemists only broke old bonds and formed new ones.
Breaking bonds requires only a fraction of the energy required to overcome the binding energy in the nucleus.
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