Bioportal Ch. 2 Study Guide

1. Polar molecules A. have bonds with an unequal distribution of electric charge. B. must form ions in water solution. C. have bonds with an equal distribution of electrical charge. D. have bonds with an overall negative charge. E. have bonds with an overall positive charge. Correct See Section 2. 2: How Do Atoms Bond to Form Molecules? Points Earned:1/1 Correct Answer:A Your Response:A 2. Hydrocarbons are _______ and _______, whereas salts are _______ and _______. A. nonpolar; hydrophobic; polar; hydrophilic B. nonpolar; hydrophilic; polar; hydrophobic C. polar; hydrophilic; nonpolar; hydrophobic D. polar; hydrophobic; nonpolar ; hydrophilic E. None of the above Correct See Section 2. 2: How Do Atoms Bond to Form Molecules? Points Earned:1/1 Correct Answer:A Your Response:A 3. The pH of coffee is close to 5 and that of pure water is 7. This means that A. coffee is more basic than water. B. water is more acidic than coffee. C. the H+ concentration of coffee is seven-fifths that of water. D. the H+ concentration of water is one-one hundredth that of coffee. E. the H+ concentration of water is one-hundred times that of coffee. Correct See Section 2. 4: What Makes Water So Important for Life? Points Earned:1/1 Correct Answer:D Your Response:D 4. Which of the following statements best describes the difference between an element and a molecule? A. An element is composed of atoms; a molecule is not. B. An element is composed of only one kind of atom; molecules can be composed of more than one kind of atom. C. An element is unstable; molecules are stable. D. Elements always have lower atomic weights than molecules. E. Elements exist in nature only as parts of molecules. Correct See Section 2. 1: How Does Atomic Structure Explain the Properties of Matter? Points Earned:1/1 Correct Answer:B Your Response:B 5. Solid salt, NaCl, is neutral. When dissolved in water, NaCl A. remains as NaCl (does not dissociate). B. dissociates to form Na– and Cl+. C. dissociates to form Na+ and Cl– ions that do not interact with water molecules. D. dissociates to form Na+ and Cl– ions that interact with water molecules. E. does not dissociate, but interacts with water molecules. Correct See Section 2. 2: How Do Atoms Bond to Form Molecules? Points Earned:1/1 Correct Answer:D Your Response:D 6. Why is the pH of a 0. 1 M solution of acetic acid in water higher than that of a 0. 1 M solution of HCl in water? A. HCl is a weaker acid than acetic acid. B. The acetic acid does not fully ionize in water, but HCl does. C. HCl does not fully ionize in water, but acetic acid does. D. Acetic acid is a better buffer than HCl. E. Acetate (ionized acetic acid) is a strong base. Correct See Section 2. 4: What Makes Water So Important for Life? Points Earned:1/1 Correct Answer:B Your Response:B 7. The reactivity of an atom arises from the A. energy difference between the s and p orbitals. B. potential energy of the outermost shell. C. average distance of the outermost shell from the nucleus. D. um of the potential energies of all electron shells. E. existence of unpaired electrons in the outermost shell. Correct See Section 2. 2: How Do Atoms Bond to Form Molecules? Points Earned:1/1 Correct Answer:E Your Response:E 8. Covalent bond formation depends on the ability of atoms to A. share electrons with other atoms. B. donate electrons to other atoms. C. receive electrons from other atoms. D. Both a and b E. All of the above Correct See Section 2. 2: How Do Atoms Bond to Form Molecules? Points Earned:1/1 Correct Answer:A Your Response:A 9. Which of the following structures molecules is incorrect? A. CH3—NH3 B. CH2=CH2 C. CH3—NH2 D. CH3—NH3+ E. CH3—CH3 Correct See Section 2. 3: How Do Atoms Change Partners in Chemical Reactions? Points Earned:1/1 Correct Answer:A Your Response:A 10. What property of water contributes most to the ability of fish in lakes to survive very cold winters? A. Water is cohesive. B. Water has a high heat capacity. C. Frozen water is more dense than liquid water. D. Frozen water is less dense than liquid water. E. Water forms hydrogen bonds. Correct See Section 2. 4: What Makes Water So Important for Life? Points Earned:1/1 Correct Answer:D Your Response:D 1. Water is essential to life. Which of the following physical properties of water affect(s) life in some beneficial way? A. Cohesiveness B. High heat capacity C. High heat of vaporization D. Ice is less dense than liquid water E. All of the above Correct See Section 2. 4: What Makes Water So Important for Life? Points Earned:1/1 Correct Answer:E Your Response:E 12. Which o f the following interactions between atoms is the strongest? A. Hydrophobic B. Ionic C. Covalent D. van der Waals E. Hydrogen bonds Correct See Section 2. 2: How Do Atoms Bond to Form Molecules? Points Earned:1/1 Correct Answer:C Your Response:C 13. Given that Avagadro's number is 6. 02 ? 1023, how many molecules of KCl would there be in 10–13 liter of a 1 M KCl solution? A. 6. 02 ? 1036 B. 6. 02 ? 1010 C. 6. 02 ? 10–10 D. 6. 02 ? 103 E. 6. 02 ? 1013 Correct See Section 2. 4: What Makes Water So Important for Life? Points Earned:1/1 Correct Answer:B Your Response:B 14. For a covalent bond to be polar, the two atoms that form the bond must have A. differing atomic weights. B. differing numbers of neutrons. C. differing melting points. D. differing electronegativities. E. similar electronegativities. Correct See Section 2. 2: How Do Atoms Bond to Form Molecules? Points Earned:1/1 Correct Answer:D Your Response:D 15. Which of the following statements about chemical reactions is false? A. They occur when atoms combine or change their bonding partners. B. Energy may be created or destroyed in a chemical reaction. C. Reactions may go to completion. D. Changes in forms of energy may accompany chemical reactions. E. The products of a chemical reaction are formed from the reactants. Correct See Section 2. 3: How Do Atoms Change Partners in Chemical Reactions? Points Earned:1/1 Correct Answer:B Your Response:B 16. Propane (CH3—CH2—CH3), is considered a nonpolar molecule because A. it does not contain oxygen. B. carbon and hydrogen have similar electronegativities. C. it is a gas. D. it is flammable. E. it forms hydrogen bonds. Correct See Section 2. 2: How Do Atoms Bond to Form Molecules? Points Earned:1/1 Correct Answer:B Your Response:B 17. Isotopes of an element A. are always unstable and radioactive. B. have different numbers of protons. C. have the same atomic weight. D. have different numbers of neutrons. E. have different numbers of electrons. Correct See Section 2. : How Does Atomic Structure Explain the Properties of Matter? Points Earned:1/1 Correct Answer:D Your Response:D 18. An element that contains ten protons and ten electrons is likely to A. form covalent bonds with another element. B. form ionic bonds with another element. C. be chemically inert (stable). D. be radioactive. E. be toxic. Correct See Section 2. 2: How Do Atoms Bond to Form Molec ules? Points Earned:1/1 Correct Answer:C Your Response:C 19. Rank the elements carbon (C), hydrogen (H), oxygen (O), and phosphorus (P) in decreasing order of the number of covalent bonds they usually form. A. C ; P ; N ; O ; H B. P ; O ; C ; N ; H C. P ; C ; N ; O ; H D. P ; C ; O ; N ; H E. P ; C ; O ; H ; N Correct See Section 2. 2: How Do Atoms Bond to Form Molecules? Points Earned:1/1 Correct Answer:C Your Response:C 20. The molecular weight of acetic acid is 60. How many grams of acetic acid would be required to prepare 10 ml of a 0. 001 M (1. 0 mM) solution? A. 6. 0 B. 0. 6 C. 0. 0006 D. 0. 06 E. 0. 006 Correct See Section 2. 4: What Makes Water So Important for Life? Points Earned:1/1 Correct Answer:C Your Response:C