Module 4 Flashcards

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0
Q

1b. define: polar molecule

A

a molecule that has slight positive and negative charges due to an imbalance in the way electrons are shared

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1
Q

1a. define: electrolysis

A

the use of electricity to break a molecule down into smaller units

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2
Q

1c. define: solvent

A

a liquid substance capable of dissolving other substances

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3
Q

1d. define: solute

A

a substance that is dissolved in a solvent

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4
Q

1e. define: cohesion

A

the phenomenon that occurs when individual molecules are so strongly attracted to each other that they tend to stay together, even when exposed to tension.

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5
Q

1f. define: hard water

A

water that has certain dissolved ions in it- predominately calcium and magnesium ions

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6
Q
  1. Suppose you did an electrolysis experiment like Experiment 4.1 on hydrogen peroxide, which has a chemical formula of h202. if it worked out properly, which of the following results would you expect:
    (a) same as with water
    (b) equal amounts of hydrogen and oxygeen
    or
    (c) twice as much oxygen as hydrogen
A

option (b); equal amounts of oxygen and hydrogen

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7
Q
  1. Suppose you did an electrolysis experiment like experiment 4.1 with a test tube that had a crack in it. Gas could slowly leak out that crack, but not nearly as quickly as it was being made in the experiment. Suppose further that the crack was in the test tube that held the oxygen gas. Which chemiclal formula might result from such a botched experiment: HO or H4O?
A

The chemical formula HO would be the more likely erroneous result.

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8
Q
  1. Epsom salts, has the chemical formula MgSO4. If Mg is the symbol for magnesium, S stands for sulfur, and O represents oxygen, how many of each atom exists in a molecule of Epsom salts?
A

one magnesium atom and one sulfur atom, four oxygen atoms

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9
Q
  1. Calcium carbonate is an ionic substance commonly called “chalk.” If this molecule has one calcium atom (Ca), one carbon atom (C), and three oxygen atoms (O), what is its chemical formula?
A

CaCO3

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10
Q
  1. One of the most common household cleaners is ammonia, which has a chemical formula of NH3. How many atoms are in a molecule of ammonia?
A

four

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11
Q
  1. A certain molecule is composed of atoms that all pull on electrons with the same strength. Will this molecule be polar?
A

no, the molecule will not be polar

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12
Q
  1. Baking soda dissolves in water. Will it dissolve in vegetable oil, which is a nonpolar substance?
A

baking soda will not dissolve in vegetable oil

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13
Q
  1. Carbon tetrachloride will not dissolve in water. Is it most likely made of ionic molecules, polar molecules or nonpolar molecules?
A

carbon tetrachloride is probably made of nonpolar molecules

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14
Q
  1. Suppose you were able to count the molecules in a substance. Which would have more molecules, 1 liter of liquid water or 1 liter of ice?
A

the liquid would have more molecules

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15
Q
  1. If the substance in question #10 were virtually any other substance, what would the answer be?
A

For nearly any other substance, the answer would be that solid would have more molecules.

16
Q
  1. What is responsible for water being a liquid at room temperature as well as for water’s cohesion?
A

hydrogen bonding

17
Q
  1. What causes surface tension?
A

cohesion

18
Q
  1. Why is water harder in certian regions of the world than in others?
A

there is a higher amount of metal-containing substances in some regions than others