Openstax

• Together, just four elements make up more than 95 percent of the body’s mass. These include ________.

  1. calcium, magnesium, iron, and carbon
  2. oxygen, calcium, iron, and nitrogen
  3. sodium, chlorine, carbon, and hydrogen
  4. oxygen, carbon, hydrogen, and nitrogen

  Oxygen, Carbon, Hydrogen, and Nitrogen
• The smallest unit of an element that still retains the distinctive behavior of that element is an ________.

  1. electron
  2. atom
  3. elemental particle
  4. isotope

  Atom
• The characteristic that gives an element its distinctive properties is its number of ________.

  1. protons
  2. neutrons
  3. electrons
  4. atoms

  Protons
• On the periodic table of the elements, mercury (Hg) has an atomic number of 80 and a mass number of 200.59. It has seven stable isotopes. The most abundant of these probably have ________.

  1. about 80 neutrons each
  2. fewer than 80 neutrons each
  3. more than 80 neutrons each
  4. more electrons than neutrons


  More than 80 neutrons each
• Nitrogen has an atomic number of seven. How many electron shells does it likely have?

  1. one
  2. two
  3. three
  4. four

  Two
• Which of the following is a molecule, but not a compound?

  1. H2O
  2. 2H
  3. H2
  4. H+

  H2
• A molecule of ammonia contains one atom of nitrogen and three atoms of hydrogen. These are linked with ________.

  1. ionic bonds
  2. nonpolar covalent bonds
  3. polar covalent bonds
  4. hydrogen bonds


  Polar covalent bonds
• When an atom donates an electron to another atom, it becomes

  1. an ion
  2. an anion
  3. nonpolar
  4. all of the above

  An ion
• A substance formed of crystals of equal numbers of cations and anions held together by ionic bonds is called a(n) ________.

  1. noble gas
  2. salt
  3. electrolyte
  4. dipole

  Salt
• Which of the following statements about chemical bonds is true?

  1. Covalent bonds are stronger than ionic bonds.
  2. Hydrogen bonds occur between two atoms of hydrogen.
  3. Bonding readily occurs between nonpolar and polar molecules.
  4. A molecule of water is unlikely to bond with an ion.

  Covalent bonds are stronger than ionic bonds
• The energy stored in a foot of snow on a steep roof is ________.

  1. potential energy
  2. kinetic energy
  3. radiant energy
  4. activation energy

  Potential energy
• The bonding of calcium, phosphorus, and other elements produces mineral crystals that are found in bone. This is an example of a(n) ________ reaction.

  1. catabolic
  2. synthesis
  3. decomposition
  4. exchange

  Synthesis
• AB→A+B is a general notation for a(n) ________ reaction.

  1. anabolic
  2. endergonic
  3. decomposition
  4. exchange

  Decomposition
• ________ reactions release energy.

  1. Catabolic
  2. Exergonic
  3. Decomposition
  4. Catabolic, exergonic, and decomposition

  Catabolic, Exergonic and Decomposition
• Which of the following combinations of atoms is most likely to result in a chemical reaction?

  1. hydrogen and hydrogen
  2. hydrogen and helium
  3. helium and helium
  4. neon and helium

  Hydrogen and Hydrogen
• Chewing a bite of bread mixes it with saliva and facilitates its chemical breakdown. This is most likely due to the fact that ________.

  1. the inside of the mouth maintains a very high temperature
  2. chewing stores potential energy
  3. chewing facilitates synthesis reactions
  4. saliva contains enzymes

  Saliva contains enzymes
• CH4 is methane. This compound is ________.

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

  Inorganic
• 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

  Sodium ions and Chloride ions
• 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

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

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

  Salt
• 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

  Ty’s blood is slightly alkaline
• C6H12O6 is the chemical formula for a ________.

  1. polymer of carbohydrate
  2. pentose monosaccharide
  3. hexose monosaccharide
  4. all of the above

  Hexose monosaccharide
• What organic compound do brain cells primarily rely on for fuel?

  1. glucose
  2. glycogen
  3. galactose
  4. glycerol

  Glucose
• Which of the following is a functional group that is part of a building block of proteins?

  1. phosphate
  2. adenine
  3. amino
  4. ribose

  Amino
• A pentose sugar is a part of the monomer used to build which type of macromolecule?

  1. polysaccharides
  2. nucleic acids
  3. phosphorylated glucose
  4. glycogen

  Nucleic acids
• A phospholipid ________.

  1. has both polar and nonpolar regions
  2. is made up of a triglyceride bonded to a phosphate group
  3. is a building block of ATP
  4. can donate both cations and anions in solution

  Has both polar and nonpolar regions
• In DNA, nucleotide bonding forms a compound with a characteristic shape known as a(n) ________.

  1. beta chain
  2. pleated sheet
  3. alpha helix
  4. double helix

  Double helix
• Uracil ________.

  1. contains nitrogen
  2. is a pyrimidine
  3. is found in RNA
  4. all of the above

  All of the above
• The ability of an enzyme’s active sites to bind only substrates of compatible shape and charge is known as ________.

  1. selectivity
  2. specificity
  3. subjectivity
  4. specialty


  Specificity