Chapter 21
Which of the following increases rate of evaporation?
Decreasing attraction between solvent molecules
How much sodium chlorate will you have to add to 100 g of water at 50º C to make a saturated solution?
123 g
Suppose 500 g of cesium chloride are stirred into 200 g of water at 20ºC. If 127 g sink to the bottom of the container, what is the solubility of cesium chloride in water at 20ºC?
187 g/100 g water
If a cube that has a length, height, and width of 4 cm is broken down into 8 cubes of equal size, what is the surface area of the eight new cubes?
192 cm2
The length, height, and width of a cube are 3 cm. If the cube is cut in half to form two rectangles, what is the total surface area of the new pieces?
36 cm2
Which of the following will make a supersaturated solution if added to 100 g of water?
40 g of NaCl if the water is 50º
Which of the following is the most precise term?
40 percent juice by volume
A cube of salt with a length, height, and width of 5 cm each is attached along a face to another cube of salt with the same dimensions. How much surface area is lost by combining the cubes to form a rectangular solid?
50 cm2
Calculate the surface area of a rectangular solid with dimension l = 2 cm, w = 1 cm, and h = 0.5 cm.
7 cm2
If a cube that is 1 cm on each side was cut in half to make two rectangles, what is the surface area of the new pieces?
8 cm2
If the length of the rectangle changes from 2 cm increases by 10% and the height and width remain at 0.5 cm & 1 cm, what is the percentage increase in surface area?
8.6 %
If 60 mg of vitamin C in a multivitamin provides 75% of the recommended daily dosage for children, how much is needed for a 100% dosage?
80 mg
Amalgams are sometimes used in tooth fillings and are made of mercury. Why is an amalgam a solution?
Amalgams are alloys and alloys are solutions.
_________ are compounds that produce solutions of ions when dissolved in water.
Electrolytes
(ionization or dissociation) Ionization has taken place if calcium phosphate (Ca3(PO4) breaks into Ca2+ and PO43- .
False
All solutes dissolve to the same extent in the same solvent?
False
This illustration indicates what effect of solutes on freezing point?
Freezing point is lower because solute particles interfere with crystal formation.
What causes soda to bubble when it is opened after shaking?
Gas bubbles are exposed to the surface and come out of solution.
How does soap clean?
Soap and a polar end and a nonpolar end. The polar end is attracted to water and the nonpolar end is attracted to oil. This takes grease and nonpolar particles away.
______ is the maximum amount of a solute that can be dissolved in a given amount of solvent at a given temperature.
Solubility
_________ is the maximum amount of a solute that can be dissolved in a given amount of solvent at a given temperature.
Solubility
How does solubility & concentration compare?
Solubility is the maximum amount of solute that can dissolve in a solvent at a given temperature. Concentration is how much is dissolved in the solvent.
How can one solvent be both a polar and nonpolar solvent?
The molecules has both a polar and nonpolar part.
Why should potatoes cook quicker in salt water than pure water?
The salt water boiling point in higher than that of regular water
Which of the following statements about solubility is generally true as the temperature decreases?
The solubility of gases increases, while the solubility of solids decreases.
How does stirring, grinding, and heating affect the rate of dissolving?
They all increase the rate.
Why is it dangerous to take large doses of some nonpolar vitamins?
They are fat soluble and can accumulate in body tissues.
What are polar and nonpolar molecules like?
Polar molecules have separate negative and positive regions. Nonpolar molecules have the same overall charge.
How does a polar and a nonpolar solvent dissolve solutes?
Polar solvents dissolve polar solutes by surrounding the charge with the opposite charge. Nonpolar solvents dissolve nonpolar solutes because they easily slip between each other..
What is the difference between relative & precise concentrations?
Relative concentration is the comparison of similar solutions with different concentrations. Precise concentration is one that is very accurate.
If 70 g of potassium bromide are dissolved in 100 g of water at 50º C, how would the solutions be described?
concentrated
the amount of solute dissolved in a solvent
concentration
Sterling silver contains 92.5 percent silver and 7.5 percent copper. Which substance is the solute?
copper
Which of the following increases rate of evaporation?
decreasing attraction between solvent molecules
The process in which water molecules draw ions away from a crystalline solid and into solution is ______.
dissociation
The process in which water molecules draw ions away from a crystalline solid and into solution is ________.
dissociation
What process is the sodium chloride in the figure undergoing?
dissociation
Which attribute enables water molecules to dissolve sugar?
electrical charge
When dissolved in water, ______ produce solutions of ions.
electrolytes
What term is NOT approprate to use when describing solutions?
heterogeneous
A ______ is a large molecule made of carbon and hydrogen atoms.
hydrocarbon
As the temperature of a liquid solvent increases, the amount of solute that can dissolve it ________.
increases
Adding a solute to a solvent _______ the freezing point of the solvent.
lowers
Gases are ______ in cooler solvents.
more soluble
Gases are _________ in cooler solvents.
more soluble
Which of the following in NOT a solution?
mud in a water tank
Air contains 78 percent nitrogen, 21 percent oxygen, and one percent argon. Which gas is the solvent?
nitrogen
Substances that do not ionize in water and cannot conduct electricity are called _______.
nonelectrolytes
Because electrons are distributed equally, a hydrocarbon is ______.
nonpolar
Because electrons are distributed equally, a hydrocarbon is _________.
nonpolar
Solvents, such as paint thinner and gasoline, evaporate more readily than water because they are what type of compounds?
nonpolar
Vitamin C is a(n) ______ compound and dissolves readily in water.
polar
Vitamin C is a(n) ________ compound and dissolves readily in water.
polar
What characteristic of water makes it the universal solvent?
polar
What can you increase to make a gas more soluble in a liquid?
pressure
Which of the following is a solution?
salt water
A solution that contains all the solute it can hold at a given temperature is ________.
saturated
a solution that contains the maximum amount of solute
saturated solution
Which of the following is not a method to alter dissolving times?
size of beaker
the maximum amount of solute that can be dissolved in a given amount of solute at a given temperature
solubility
A ______ is the substance being dissolved in a solution.
solute
the substance being dissolved (usually a solid)
solute
A mixture that appears to have the same composition, color, and density and is mixed at the molecular level is called a(n) ______.
solution
A mixture that appears to have the same composition, color, and density and is mixed at the molecular level is called a(n) _________.
solution
When iodine is dissolved in alcohol, what term is used to describe the alcohol?
solvent
the substance doing the dissolving (usually a liquid)
solvent
Which of the following actions increases the rate of dissolving?
stirring the solution
If a solute crystallizes out of a solution when a seed crystal is added, what kind of solution is it?
supersaturated
What type of solution do you have if you can add more solute and it dissolves?
unsaturated
any solution that can contain more of the solute
unsaturated solution
How does the concentration of a solute in a solution influence its boiling point and freezing point?
As the concentration increases the boiling point increases and the freezing point decreases.
How does keeping a capped carbonated beverage in the fridge keep it from going flat?
Cool beverages can contain more carbon dioxide and a capped container keep the pressure higher. This means more carbon dioxide remains in the beverage.
By volume, orange drink is 10% each of orange juice and corn syrup. A 1.5-L can of drink costs $0.095. A 1.5-L can of orange juice is $1.49, and 1.5 L of corn syrup is $1.69. Per serving, does it cost less to make your own orange drink or buy it?
Making it is less.
Which of the following statements is true?
Nonpolar solvents are useful for dissolving nonpolar solutes.
What would most likely happen to your hands if you wash too often?
You would lose the natural oils your skin produces and your hand would become cracked and rough.
What can a polar solvent dissolve?
a polar solute
What word is used to describe a mixture that is 85% copper and 15% tin?
alloy
a mixture of metals with similar properties
alloy
