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BIO 140 Human Biology I - Questions and Solutions

Inorganic Compounds Essential to Human Functioning - Solutions

Review Questions

1. CH4 is methane. This compound is ________.

  1. inorganic
  2. organic
  3. reactive
  4. a crystal

2. Which of the following is most likely to be found evenly distributed in water in a homogeneous solution?

  1. sodium ions and chloride ions
  2. NaCl molecules
  3. salt crystals
  4. red blood cells

3. Jenny mixes up a batch of pancake batter, then stirs in some chocolate chips. As she is waiting for the first few pancakes to cook, she notices the chocolate chips sinking to the bottom of the clear glass mixing bowl. The chocolate-chip batter is an example of a ________.

  1. solvent
  2. solute
  3. solution
  4. suspension

4. A substance dissociates into K+ and Cl– in solution. The substance is a(n) ________.

  1. acid
  2. base
  3. salt
  4. buffer

5. Ty is three years old and as a result of a “stomach bug” has been vomiting for about 24 hours. His blood pH is 7.48. What does this mean?

  1. Ty’s blood is slightly acidic.
  2. Ty’s blood is slightly alkaline.
  3. Ty’s blood is highly acidic.
  4. Ty’s blood is within the normal range

 

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Critical Thinking Questions

1. The pH of lemon juice is 2, and the pH of orange juice is 4. Which of these is more acidic, and by how much? What does this mean?

Solution: Lemon juice is one hundred times more acidic than orange juice. This means that lemon juice has a one hundred-fold greater concentration of hydrogen ions.

2. During a party, Eli loses a bet and is forced to drink a bottle of lemon juice. Not long thereafter, he begins complaining of having difficulty breathing, and his friends take him to the local emergency room. There, he is given an intravenous solution of bicarbonate. Why?

Solution: Lemon juice, like any acid, releases hydrogen ions in solution. As excessive H+ enters the digestive tract and is absorbed into blood, Eli’s blood pH falls below 7.35. Recall that bicarbonate is a buffer, a weak base that accepts hydrogen ions. By administering bicarbonate intravenously, the emergency department physician helps raise Eli’s blood pH back toward neutral.

 

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OpenStax, Inorganic Compounds Essential to Human Functioning. OpenStax CNX. Feb 25, 2016 http://cnx.org/contents/e4e45509-bfc0-4aee-b73e-17b7582bf7e1@4. © Feb 25, 2016 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License 4.0 license.