Ch 2 & 3 Review Sheet Answers (from Review Sheet Given in Class)10pm 5/13

1 They are isotopes.

3. eight neutrons

5. 1

7. 5

9.) carbon, hydrogen, nitrogen, and oxygen

11. a hydrogen bond

13. versatility as a solvent

15. gastric juice at pH 2

17. 4

19 S

21 iodine

23 one of the atoms sharing electrons is much more electronegative than the other atom.

25 chlorine gains an electron from sodium.

27 eight neutrons.

29 an isotope.

31 They form covalent bonds in aqueous solutions. & They are particularly stable and unreactive

33 molecules

35 4

37 nonpolar covalent bonds.

39 electrons in the outer valence shell in the atom.

41 be particularly stable and nonreactive

43 ions

45 They all have unpaired electrons in their valence shells.

47 There is no clear distinction because the two sciences are parts of same whole.

49 The solution is neutral &The concentration of H+ ions is 10-7 moles per liter.

51 hydrogen bonds

53 hydrogen bonds

55 versatility as a solvent

57 gastric juice at pH 2

59 1000 times more

61 Compared to most liquids, the evaporation of water requires a large amount of heat.

63 1 x 10-9 moles of hydroxide ion per liter of lake water & 9.0 molar with regard to hydroxide ion concentration

65 concentration of H+ has increased to 10 times what it was at pH

67 tend to maintain a relatively constant pH.

69 4'C

71 the water molecule is shaped something like a right angle. the water molecule is polar. the oxygen atom in a water molecule is weakly negative. the hydrogen atoms in a water molecule are weakly positive.

73 four

75 the formation of hydrogen bonds releases heat.

77 absorption and release of heat when hydrogen bonds break and form

79 hydrogen bonds

81 E