Chapter 3
Which of the following solutions has the greatest concentration of hydrogen ions [H+]
gastric juice at pH 2
Desert rabbits are adapted to the warm climate because their large ears aid in the removal of heat due to the
high heat of vaporization of water
What determines the cohesiveness of water molecules
hydrogen bonds
Which bonds must be broken for water to vaporize
hydrogen bonds
Hydrophobic substances such as vegetable oil are
nonpolar substances that repel water molecules
In a single molecule of water, the two hydrogen atoms are bonded to a single oxygen atom by
polar covalent bonds
Which of the following solutions has the greatest concentration of hydroxide ions [OH-]
seawater at pH 8
An example of a hydrogen bond is the bond between
the H of one water molecule and the O of another water molecule
Water is able to form hydrogen bonds because
the bonds that hold together the atoms in a water molecule are polar covalent bonds
One mole (mol) of a substance is
- 6.02 × 1023 molecules of the substance. - the molecular mass of the substance expressed in grams
Buffers are substances that help resist shifts in pH by
- donating H+ to a solution when they have been depleted - accepting H+ when they are in excess
What do cohesion, surface tension, and adhesion have in common with reference to water
All are properties related to hydrogen bonding
Which of the following ionizes completely in solution and is considered to be a strong acid
HCl
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.
At what temperature is water at its densest
4°C
What is true when an ice cube cools a drink
Kinetic energy in the drink decreases
Which of the following ionizes completely in solution and is considered to be a strong base
NaOH
What statements is true about buffer solutions
They maintain a relatively constant pH.
The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called
a hydrogen bond
Water's high specific heat is mainly a consequence of the
absorption and release of heat when hydrogen bonds break and form
The formation of ice during colder weather helps moderate the seasonal transition to winter. This is mainly because
the formation of hydrogen bonds releases heat
Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon
the release of heat by the formation of hydrogen bonds