practice test 2
which of the following solutions is the most concentrated?
0.5 L of a 3 molar solution
If the solubility of a compound is 30 grams per liter, how much solid is left undissolved if you mix 30 g of the compound in 0.33 L of solution?
20g
How many molecules of sucrose are in a 0.500 moles of sucrose?
3.01 x 1023 molecules of sucrose
If the solubility of a compound is 72 grams per liter at a given temperature, how many grams of the compound will dissolve in 0.50 liters at the same temperature?
36g
How many valence electrons does bromine (Br, atomic no. = 35) have?
7
How is the solubility of a gas affected by temperature?
As temperature goes down, the solubility goes up
Which of the following might have the lowest solubility in water?
CH3CH3
Which of the following molecules is most likely to show a dipole-dipole interaction?
CH3OH
How is it possible for a neutral molecule, such as water, to form an ion?
It can combine with a hydrogen ion to form a positively charged species.
Red blood cells have a high concentration of dissolved ions. When placed into pure water they rupture. Why?
Osmosis draws water into the cell until it pops
Phosphine is a covalent compound that contains phosphorus, P, and hydrogen, H. What is its chemical formula?
PH3
Which of the following molecules is most likely to show a dipole-dipole interaction?
SO2
How are intermolecular forces and solubility related?
Solubility depends on the solvent's ability to overcome the intermolecular forces in a solid
Fish don't live very long in water that has just been boiled and brought back to room temperature. Suggest why.
The boiling process removes most of the air that was dissolved in the water. Upon cooling the water is void of its usual air content, hence, the fish drown.
What happens if you were to place a concentrated solution into a bag made of a semipermeable membrane and were to then suspend it in a very dilute solution?
The size of the suspended bag would increase
The valence electron of a sodium atom does not sense the full +11 of the sodium nucleus. Why not?
There are two inner shells of electrons containing ten electrons shielding the sodium nucleus from sensing it.
Would you expect to find more dissolved oxygen in polar or tropical ocean waters? Why?
There would be more dissolved oxygen in the polar oceans because the solubility of oxygen in water decreases with increasing temperature.
a soap molecule is
a molecule with both a polar and nonpolar part
Which of the following solutions is the most dilute?
all the same
Which of the following is the weakest form of interatomic attraction?
an induced dipole-induced dipole interaction
Polar molecules tend to be ________.
asymmetrical
The separation of charges within a polar molecule is called a
dipole
A dipole is a
separation of charges
Fluorine is a relatively
small atom
Cells at the top of a tree have a higher concentration of sugars than cells at the bottom. How might this fact assist a tree in moving water upward from its roots?
water is pushed upwards by osmotic pressure
