BSC1010 -Chapter 3- Test Review
Hydrophobic
"water-fearing"; pertaining to nonpolar molecules (or parts of molecules) that do not dissolve in water.
Hydrophilic
"water-loving"; pertaining to polar or charged molecules (or parts of molecules) that are soluble in water
Water's high specific heat is mainly a consequence of the...? -the small size of the water molecules -high specific heat of oxygen and hydrogen atoms -absorption and release of heat when hydrogen bonds break and form -fact that water is a poor heat conductor -the inability of water to dissipate heat into dry air
-absorption and release of heat when hydrogen bonds break and form
Why does water display unique properties like cohesion, heat capacity, and making ice float? -because of the covalent bonds between the oxygen and hydrogen -because of its ability to hydrogen bond -because of its ability to make and break ionic bonds -because the electrons are shared equally between the oxygen and hydrogen atoms
-because of its ability to hydrogen bond
What property of water is responsible for water transport upward in plants? -moderation of temperature -insulation -its versatility as a solvent -cohesion and adhesion -its role as a buffer
-cohesion and adhesion
Which of the following phenomena is most likely due to the high cohesiveness of water? -lakes and rivers freeze from the top down, not the bottom up -the "Jesus lizard" can run across the surface of liquid water for short distances -adding salt to snow makes it melt -the temperature of Santa Monica Bay fluctuates less than the air temperature throughout the year -all of the above due to the cohesiveness of water
-the "Jesus lizard" can run across the surface of liquid water for short distances
Which of the following statements is true about buffer solutions? -they maintain a constant pH when bases are added to them but not when acids are added to them -they maintain a constant pH when acids are added to them but not when bases are added to them -they maintain a constant pH of exactly 7 in all living cells and biological fluids -they maintain a relatively constant pH -They are found in only living systems and biological fluids
-they maintain a relatively constant pH
A solution of pH 3 is 100 times more acidic than a solution of pH 5. -true -false
-true
At what temperature is water the most dense?
4°C
polar
Molecule with partial charges. Mixes with water; regions at the surface of the micelle
base
a compound that produces hydroxide ions and decreases hydrogen ion concentration in a solution
Non-polar
a molecule in which all atoms have the same electronegativity and the electron distribution is equal; doesn't mix with water; regions at the interior of the micelle
amphipathic
a molecule that has both a hydrophilic region and a hydrophobic region.
adhesion
an attraction between molecules of different substances
cohesion
an attraction between molecules of the same substance
acid
compound that forms hydrogen ions (H+) in solution
base pH
greater than 7
Why can water moderate temperature?
hydrogen bonds can tolerate changes in temperature
Why does ice float in liquid water?
hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
charged molecules
ions; polar molecules are partially charged
Acid pH
less than 7
Why does water have a high specific heat?
much of the added energy is required to break hydrogen bonds.
Anions
negatively charged ions
Cations
positively charged ions
example of cohesion
surface tension
example of adhesion
water and plant cell walls
Buffers
weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH