1. A bond in which two atoms share electrons but there is an unequal attraction for the shared electrons is a(n) • Ionic bond • Polar covalent bond • Nonpolar covalent bond • Hydrogen bond
2. A hydrogen bond is a • The bond between a hydrogen atom and a oxygen atom in a water molecule • The bond between a hydrogen atom and a nitrogen atom in an ammonia molecule • The attraction between opposite poles of polar covalent molecules • All of the above • Both A and B
The bond within a water molecule is a polar covalent bond. A hydrogen bond is an attraction between two different water molecules (or other polar molecules). This attraction occurs because the polar covalent bond creates charged poles in each molecule (oxygen end is negatively charged and hydrogen pole is positively charged.) The oxygen end of one molecule is attracted to a hydrogen end of another.
3. Water molecules stick together, creating surface tension, due to the attraction between opposite poles of water molecules forming hydrogen bonds. This ability to stick together means that water is _______. • Adhesive • Cohesive • Hydrophobic
Cohesion = the attraction between like molecules Adhesion = the attraction between different types of molecules Water is both cohesive (between water molecules) and adhesive with many molecules..
4. The term hydrophilic means that a substance • is highly reactive • Is chemically inert (does not react) • is attracted to water • Is repelled by water
5. Which of following types of substances are hydrophilic? I. Nonpolar covalent II. Polar covalent III. Ionic • I only • II only • III only • I and II • I and III • II and III
Since water is a polar molecule, it attracts both ionic compounds (since charged ions are attracted to the partially charge poles of the water molecule) and other polar compounds (since the oppositely charged poles are attracted to water’s charged poles.)
6. A substance that is able to dissolve another substance is called a • Solute • Solvent • Solution • Reactant • Both A and D
7. It takes ____ energy to change water’s temperature compared to most other substances, so water tends to _________ • More, moderate temperatures • More, cause more extreme temperature changes • Less, moderate temperatures • Less, cause more extreme temperature changes
8. A substance with a low pH is _________ and has a higher concentration of ____ ions. • Acidic; OH- • Acidic; H+ • Basic (Alkaline); OH- • Basic (Alkaline); H+
9. A substance with a pH of 2 is __ than a substance with a pH of 7. • 5 x less acidic • 5 x more acidic • 50 x less acidic • 50 x more acidic • 100,000 x less acidic • 100,000 x more acidic
B C B C F B A B F