- A saturated solution of compound X in water has a greater concentration than does a saturated solution of compound Y. Does it follow that compound X is also more soluble in water?
Your answer:
none of these
No, The greater the concentration of a compound in water, the less soluble it is.
Yes, compound X is more soluble than is compound Y because a greater concentration in water can be obtained.
No, concentration of a solution is not correlated with how soluble that solution is in water.
Since both solutions are saturated, it cannot be determined which compound has a greater solubility.
- Many solvents expand to occupy greater volumes with increasing temperature. What happens to the concentration of a solution made with such a solvent as its temperature is increased?
Your answer:
not enough information
The concentration of a solution increases as the solute fits into the new spaces between the molecules.
Since concentration depends on how much mass is dissolved in a given volume, as the volume increases, the concentration decreases.
Since it has a greater ability to dissolve more solute at a higher temperature, its concentration has decreased.
Since it has a greater ability to dissolve more solute at a higher temperature, its concentration has increased.
- If nitrogen, N2, were pumped into your lungs at high pressure, what would happen to its solubility in your blood stream?
Your answer:
Nitrogen is not soluble in your blood.
The greater the pressure, the lower the solubility.
The greater the pressure, the greater the solubility.
You cannot change solubility of a substance by changing the pressure.
- The air that a scuba diver breathes is pressurized to counteract the pressure exerted by the surrounding water. Under these conditions, excessive amounts of nitrogen dissolves in bodily fluids, such as blood. If the diver ascends to me surface too rapidly, the excessive nitrogen bubbles out of the bodily fluids-much like carbon dioxide bubbles out of a soda immediately after its has been opened. This results in a painful and potentially lethal medical condition known as the bends. Why does breathing a mixture of helium and oxygen rather than air help divers to avoid getting the bends?
Your answer:
Helium is a smaller molecule than nitrogen, so when it bubbles out of solution, it is less painful and less harmful to the body.
The nitrogen in the blood will bind to helium, and so will be exhaled rather man being stuck in the blood.
Oxygen and helium have stronger attractions for each other than they do for me blood, so less helium will be dissolved in the blood and to cause die bends.
The helium is less soluble in the bodily fluids and so less dissolves for a given pressure. Upon decompression, there is less helium to "bubble out" and cause potential harm.
- Suggest why sodium chloride, NaCl, is insoluble in gasoline. Consider the electrical attractions.
Your answer:
Since this molecule is so small, there is not much opportunity for the gasoline to interact with it through any electrical attractions.
Since gasoline is a very polar molecule, the salt can only form dipole-induced dipole bonds, which are very weak, giving it a low solubility in gasoline.
Since gasoline is so strongly attracted to itself, the salt, NaCI is excluded.
Salt is composed of ions that are too attracted to themselves. Gasoline is non-polar so salt and gasoline will not interact very well.
- How necessary is soap for removing salt from your hands?
Your answer:
Soap is necessary because it has both a polar and nonpolar end to interact with the positive and negative ions in the salt.
Soap is not necessary because there are no electrical charges on the skin of your hands for the salt to interact with.
Soap is necessary because it creates a film on the surface of your skin, shielding it from interacting with the ionic charges of the salt.
Soap is not at all necessary for removing salt from your hands. The strong ion-dipole interactions between fresh water and the salt are most sufficient to lift the salt away from your hands.
- "Hard water" is water that
Your answer:
contains many dissolved gases.
contains a relatively large amount of calcium and magnesium ions.
is difficult to obtain.
none of the above
- "Soft water" is water that
Your answer:
is difficult to obtain.
contains many dissolved gases.
contains a relatively large amount of calcium and magnesium ions.
none of the above
- Hard water is undesirable because
Your answer:
it tends to remove calcium and magnesium ions from your body.
its ions tend to accumulate in pipes.
Two of the above are correct.
its ions tend to complex with soap forming a scum.
- How can nonpolar argon atoms induce dipoles in other nonpolar argon atoms?
Your answer:
Random motions of electrons permit the formation of weak momentary dipoles.
The positively charged argon nucleus induces a dipole in the neighboring argon atom.
By physically colliding with mem, thus knocking the electrons to one side.
They cannot.
- It is difficult to induce a dipole in a fluorine atom because
Your answer:
fluorine is always found bonded to other atoms.
electrons in fluorine move very slowly due to the large effective nuclear charge.
the rate of collision between the atoms is low and dipoles are not so easily induced.
electrons find it difficult to group to one side because of fluorine's small size.
- The boiling point of isooctane, C8H18, is much higher man the boiling point of methane, CH4 because of
Your answer:
the large size of isooctane molecules.
electric repulsion.
more hydrogen atoms.
more hydrogen bonds.
- How does a solid phase differ from a liquid phase on the molecular level?
Your answer:
The molecules of a solid are fixed, while the molecules of a liquid are mobile.
The molecules of a solid are always more compact.
Solids have crystalline structure while liquids are amorphous.
There are molecular attractions in the solid phase but not in the liquid phase.
- Dipole-induced dipole forces of attraction exist between water and gasoline, and yet these two substances do not mix because water has such a strong attraction for itself. Which of the following compounds might best help to make these two substances mix into a single liquid phase?
Your answer:
the molecule in the middle because when the salts mix into the water, it will help separate the water and decrease the attraction for itself
All of these molecules would be equally effective at increasing the mixing of gasoline and water.
The molecule on the right will form attractions with the polar ends of the water, allowing the gasoline a chance to mix with the water.
the molecule on the far left because the O-H bond is polar and the carbon and hydrogen bonds are nonpolar