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1 | |
What combination of properties would be typical of a molecular compound, such as sucrose (table sugar)? |
| | A) | low melting point, electrolyte |
| | B) | high melting point, electrolyte |
| | C) | low melting point, non-electrolyte |
| | D) | high melting point, non-electrolyte |
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2 | |
Calcium bromide is an electrolyte. In solid form, it is crystalline. What other combination of properties is calcium bromide likely to possess? |
| | A) | electrical conductor in solid state, high melting point |
| | B) | electrical conductor in solid state, low melting point |
| | C) | non-conductor of electricity in solid state, high melting point |
| | D) | non-conductor of electricity in solid state, low melting point |
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3 | |
What property is common to the chemicals nicotine (found in cigarettes), caffeine (found in coffee, tea, and many soft drinks), and ethanol (found in alcoholic beverages)? |
| | A) | have no known toxic effects |
| | B) | are government regulated as hazardous substances |
| | C) | are absorbed in such small amounts that they produce no serious physical effects |
| | D) | pose a heath hazard if used excessively |
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4 | |
A pure substance is not a metal, but it conducts electricity somewhat when dissolved. What can you infer about its composition? |
| | A) | is either an ionic or a molecular compound |
| | B) | is neither ionic nor molecular |
| | C) | is definitely ionic |
| | D) | is definitely molecular |
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5 | |
Why are most pure molecular substances non-conductors of electricity? |
| | A) | They are made of ions. |
| | B) | They are made of neutral molecules. |
| | C) | They are made of uncharged neutrons. |
| | D) | Their positive and negative molecules cancel out. |
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6 | |
What does the low melting point of a molecular compound suggest about the forces between particles in the substance? |
| | A) | strong forces between molecules |
| | B) | weak forces between molecules |
| | C) | strong forces within molecules |
| | D) | weak forces within molecules |
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7 | |
Most ionic compounds have relatively high melting points. What inference about the structure of ionic compounds does this observation suggest? |
| | A) | They are made up of individual molecules. |
| | B) | They are made of ions arranged in a crystal lattice. |
| | C) | The bonding forces in them are very weak. |
| | D) | The bonding forces in them are very strong. |
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8 | |
Which property of ionic substances leads scientists to infer that ionic substances can break down into mobile, electrically-charged particles? |
| | A) | regular crystalline form in solid state |
| | B) | relatively high melting points |
| | C) | conduct electricity when melted or dissolved |
| | D) | do not conduct electricity in solid state |
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