CH 19 PRACTICE TEST

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CH 19 PRACTICE TEST
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TRUE/FALSE

• Acids will turn litmus paper red.

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• True

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• Bases feel slippery and taste sour.

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• False/bitter

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• Bases form hydrogen ions (H) when dissolved in
  water.

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• False/hydroxide ions

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.

• The pH is a scale used to measure the
  concentration of hydrogen ions.

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• True

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• The products of a neutralization reaction are
  acids and bases.

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• False/water and salt

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• Concentration is the process of breaking down
  complex molecules of foods into smaller molecules.

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• False/digestion

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MULTIPLE CHOICE
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• A substance that tastes bitter, feels slippery,
  and turns red litmus paper blue is a ___

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• base.

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• Which is a characteristic property of acids?

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• A. they turn blue litmus red
• B. they turn red litmus blue

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• Acids are described as corrosive because they

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• eat away at other materials

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• Which is a likely use for a base?

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• A. etching metals for printing
• B. making soaps and detergents

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• Any substance that forms hydrogen ions (H) in
  water is an

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• acid

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• In water, bases form.

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• Hydroxide ions

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• The pH scale measures

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• The concentration of hydrogen ions

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• If a solution has a pH of 9, the solution is .

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• basic

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• Neutralization is a reaction between a(n)

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• Acid and a base

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• What does a neutralization reaction produce?

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• Water and a salt

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• The process that breaks down complex molecules of
  food into smaller molecules is called

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• digestion

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• Which process tears, grinds, and mashes large
  food particles into smaller ones?

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• Mechanical digestion

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• How is pH important during digestion?

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• Different enzymes work better at different pH
  values.

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• Compared to the pH of the mouth and the small
  intestine, the pH of the stomach is

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• lower

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• Normal rainfall is slightly acidic, which means
  its ph must be.

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• Between 5 and 7

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• What do enzymes in the digestive system do?

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• Speed up chemical digestion

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• Acids present in food are safe to eat because
  they usually are

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• weak

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• You can find the pH of a substance by using the
  proper type of.

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• indicator

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COMPLETION
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• A(n) ____ is a compound that tastes sour and
  reacts with some metals.

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• acid

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• A(n) ____ is a compound that turns litmus blue
  and is often found in soaps and detergents.

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• base

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• Substances that form hydrogen ions when released
  in water are called ____.

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• acids

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• When the pH is high, the concentration of
  hydrogen ions is____.

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• low

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• In a reaction of an acid with a base, the pH
  changes to a value that is closer to ____.

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• 7 (neutral)

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• _________ digestion tears, grinds, and mashes
  large food particles into smaller particles.

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• Mechanical

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• Chemical digestion happens with the help of
  ________ that are sensitive to pH.

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• enzymes

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• At the same concentrations, strong acids produce
  more _______ ___ than weak acids.

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• Hydrogen ions

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• Foods such as oranges, tomatoes, and apples have
  a pH that is_______ than 7.

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• Less (lower)

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• A(n) _____ is an ionic compound produced from the
  neutralization of an acid with a base.

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• salt

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• Digestion breaks down ____ into simpler
  substances that your body can use for raw
  materials and energy.

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• foods

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• The organ with the most acidic contents in the
  digestive system is the _________.

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• stomach

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• Acids are _____, which means that they eat away
  at other materials.

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• corrosive

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SHORT ANSWER

• TURN TO PAGE 619 IN YOUR BOOK TO LOOK AT THE pH
  SCALE.

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• Use the pH scale to predict how the taste of an
  apple and a lemon would compare.

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• Lemon is more sour

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• Which has a more sour taste?

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• lemon

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• Explain

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• Lemon is lower on the pH scale so it is more
  acidic

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• In terms of pH, explain what would happen if you
  mixed vinegar with a solution of ammonia.

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• The resulting mixture would be closer to neutral

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• What type of products would form?

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• A salt and water

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• What does the pH of drain cleaner tell you about
  the dangers of such a product?

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• Its very high pH tells you that it could burn or
  damage your skin

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• What color would litmus paper turn in a solution
  of baking soda?

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• blue

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• Explain your answer in terms of pH

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• Baking soda is a base, its pH is higher then 7
  therefore it would change red litmus to blue.

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• Why does soap taste bitter?

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• Soap is a base and bases taste bitter.

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• What does the pH of water tell you about how the
  water differs from the other items shown in the
  diagram?

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• Waters pH is 7 or neutral. It is not an acid or
  a base.

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ESSAY
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• Describe how solutions of acids and bases differ
  in terms of particles. How do the differences
  relate to the properties of acids and bases?

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• Describe the changes in pH that occur as food
  passes through your digestive system. Why are
  these changes important?

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• Explain the roles of chemical and mechanical
  digestion in preparing food for use in the body.

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• You are given three clear, colorless, unknown
  solutions, and red and blue litmus papers.
  Describe the steps you might take to correctly
  identify each solution as acidic, basic, or
  neutral.

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• Describe the neutralization process and give an
  example of the reaction using hydrochloric acid
  (HCl) and potassium hydroxide (KOH).