HW 2

because of many hydrogen bonds that form between its molecules, water has a very high ____. This allows small insects to "walk on water"

surface tension

cause of the high surface tension of water

water molecules attract each other

When 1 g of sugar (sucrose) is dissolved in 500 mL of water, ____ is the solvent and ____ is the solute.

water, sugar

arrange the states of water in order from most dense to least dense

1. liquid 2. solid 3. gas

why is solid water less dense than liquid water?

as the movement of water molecule slows down, hydrogen bonds form that space the molecules relatively far apart

the ability of water to rise inside a tube of narrow diameter against the pull of gravity is called:

capillary action

water consists of one oxygen atom joined to two hydrogen atoms by what type of bond?

covalent

substance that attract water are called ____ ("water-loving") while substances that repel against water are called ____ ("water-fearing").

hydorphilic, hydrophobic

when a sugar crystal is placed in water, every time a sucrose molecule dissociates from the crystal, water molecules surround it in a cloud forming a(n) ____ shell that prevents it from associating with other sucrose molecules.

hydration

Consider a large protein molecule that has some parts that are highly hydrophobic. When placed in a water solution, the protein folds in a globular shape, such that all the hydrophobic portions are inside the molecules, away from water. This is an example of :

hydrophobic exclusion

what does it mean when we say water is adhesive?

it is attracted to other polar molecules and ions

Fish and other animals can survive at the bottom of a lake during winter because ice is ____ dense than liquid water

less

hydrophobic molecules

non polar molecules, hydrocarbon chains (chains composed of carbon and hydrogen atoms), and oils

water tends to repel or exclude:

nonpolar molecules, hydrophobic molecules

A hydrogen bond can form between the partially negative ____ atom of one water molecule and the partially positive ____ atom of another water molecule.

oxygen, hydrogen

Water carries two partially negative charges on the _____ atom and two partially positive charges, on on each ____ atom.

oxygen, hydrogen

Water carries two partial ____ charges on the oxygen atom and two partial ____ charges, one on each hydrogen atom.

positive, negative

hydrophobic exclusion refers to

the tendency of non-polar molecules to clump together in water

water rises inside a glass tube with narrow diameter for which reason?

there are electrical charges on the surface of the glass

Water is cohesive. What describes this feature of water molecules?

they are attracted to each other

A(n) ____ molecule can break apart to form a positive hydrogen ion and a negative hydroxide ion.

water