homework 3

Suppose that I have one liter of water in which the ionization of water has reached equilibrium. What is the concentration of H+ ions? ****

1/10,000,000 moles/liter 10 raised to the -7th power moles/liter 10 raised to the 7th power moles/liter * a and b b and c The correct choice is 10 raised to the -7 moles/liter. However, this is equal to 1/10,000,000 moles/liter

Which statements (or statements) describes a substance that is hydrophilic? ***

A hydrophilic substance does dissolve in water

Which statement (or statements) describes a hydrophobic substance?

A hydrophobic substance typically has large number of non-polar covalent bonds

Which statement describes a solution? ***

A solution is a disolving agent that is always a liquid A solution is a substance (solid, liquid, or gas) that is disolved A solution is a gas that consists of homogenous mixture of two or more substances A solution is a solid that consists of homogenous mixture of two or more substances * None of the above However, a solution is always a liquid. It is never a gas or solid.

True or false? A body of water has a high specific heat because energy that is absorbed by the body must break ionic bonds between H+ and OH- ions before it can increase their kinetic energy

False While the statement is partially true, energy that is absorbed by a body of water must break hydrogen bonds between water molecules not ionic bonds. Water is not an ionic compound.

Which statement (or statements) accurately describes the concept of heat?

For a defined body of matter, heat is the average kinetic energy of its atoms or molecules For a defined body of matter, heat is the total kinetic energy of all its atoms or molecules The heat contained in a defined body of matter deponds on the body's volume a and b * b and c Heat is defined as the total kinetic energy of all the atoms/molecules within a body of matter. THEREFORE, the heat of a body of matter depends on its overall size/volume, and choice (b) and (c) are correct.

In the liquid phase of water, multiple water molecules are held together by...

Hydrogen bonds

In a single molecule of water, the oxygen atom is bonded to two hydrogen atoms by... ****

Polar covalent bonds In a single molecule of water, the oxygen atom is bonded to the two hydrogen atoms by polar covalent bonds. CONSEQUENTLY, water molecules are polar and can hydrogen bond to each other.

True or false? In the solid phase of water, each water molecule is hydrogen bonded to four other water molecules; and the hydrogen bonds are of maximum length. ****

True Both statements are true. THEREFORE, the correct answer is true. Because the water molecules in ice are spaced further apart, a given volume of ice is less dense than the same volume of liquid water.

True or false? In liquid water, a single water molecule is hydrogen bonded to an average of 3.4 other water molecules. Hydrogen bonding among water molecules causes them to cling together making bodies of water cohesive. ****

True Both statements are true. Thus, the entire statement is true. All the emergent properties of bodies of water depend to one degree or another on hydrogen bonding among water molecules.