Exam 5 Chapter 16
Which of the following material phases cannot form a solution? A) solids B) liquids C) gases D) All of the above can form solutions.
D) All of the above can form solutions: A) solids B) liquids C) gases
What is the difference between a compound and a mixture? A) A mixture can be physically separated into its components; a compound cannot be physically separated into its components. B) A compound can be physically separated into its components; a mixture cannot be physically separated into its components. C) A compound is just a mixture of elements. D) The components of a mixture do not have the same properties individually as they do when mixed. E) The components of a compound have the same properties individually as they do when mixed.
A) A mixture can be physically separated into its components; a compound cannot be physically separated into its components.
What is the easiest way to eliminate organic components? A) Aerate the solution and let bacteria consume the organics. B) Treat the solution with UV radiation. C) Filter the solution through activated carbon filters. D) reverse osmosis
A) Aerate the solution and let bacteria consume the organics
How is the solubility of a solid affected by temperature? A) As temperature goes up, the solubility goes up B) As temperature goes up, the solubility goes down.
A) As temperature goes up, the solubility goes up
Which of the following describes reverse osmosis? A) High pressure saltwater is forced against a semipermeable membrane and fresh water comes out. B) Saltwater is chemically reacted with aluminum particles, which chemically binds to the chloride ions. C) The water is heated until it evaporates and condenses in a pure form. D) High pressure saltwater is reacted with aluminum, which absorbs the sodium ions in an oxidation reaction.
A) High pressure saltwater is forced against a semipermeable membrane and fresh water comes out.
What is an advantage of using chlorine gas to disinfect drinking water supplies? A) It provides residual protection against pathogens. B) It gives the water a fresh taste. C) Residual chlorine in water helps to whiten teeth. D) Excess chlorine is absorbed in our bodies as a mineral supplement.
A) It provides residual protection against pathogens.
Red blood cells have a high concentration of dissolved ions. When placed into pure water they rupture. Why? A) Osmosis draws water into the cell until it pops. B) Water dissolves the cell membrane. C) Osmosis draws water out of the cell until it tears. D) The cells are not stable outside of a biological host.
A) Osmosis draws water into the cell until it pops.
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? A) Since concentration depends on how much mass is dissolved in a given volume, as the volume increases, the concentration decreases. B) The concentration of a solution increases as the solute fits into the new spaces between the molecules. C) Since it has a greater ability to dissolve more solute at a higher temperature, its concentration has decreased. D) Since it has a greater ability to dissolve more solute at a higher temperature, its concentration has increased.
A) Since concentration depends on how much mass is dissolved in a given volume, as the volume increases, the concentration decreases.
How are intermolecular forces and solubility related? A) Solubility depends on the solvent's ability to overcome the intermolecular forces in a solid. B) Solubility depends on the solute's ability to overcome the intermolecular forces in the solvent. C) Solubility is a measure of how strong a solvent's intermolecular forces are. D) Solubility is a measure of how weak the intermolecular forces in the solute are.
A) Solubility depends on the solvent's ability to overcome the intermolecular forces in a solid
Why is secondary treatment often needed for sewage? A) The dissolved organics are too high and lead to bacterial growth. B) The solution is contaminated with dangerous bacteria. C) There are too many dissolved inorganic compounds. D) There are too many finely divided particles that need to be filtered.
A) The dissolved organics are too high and lead to bacterial growth.
If you were to increase the pressure of a gas above a liquid (such as by pressing a piston above a liquid) what happens? A) The gas is forced into solution and the solubility increases. B) The solution is compressed and the gas is forced out of the solvent. C) The pressure goes down and the gas moves out of the solvent. D) The pressure goes down and the gas goes into the solvent. E) The amount of gas in the solution would stay the same.
A) The gas is forced into solution and the solubility increases.
Which of the following accurately describes osmosis? A) The more concentrated solution absorbs water from the less concentrated solution. B) The less concentrated solution absorbs water from the more concentrated solution. C) The less concentrated solution gets more dilute. D) The ions migrate from the more concentrated solution to the less concentrated.
A) The more concentrated solution absorbs water from the less concentrated solution.
What is the special property of a semipermeable membrane that makes osmosis possible? A) The pores in the membrane only allow water to pass through. B) Water only moves through the membrane in one direction. C) Only the ions travel through the membrane. D) Ions only move one way through the membrane.
A) The pores in the membrane only allow water to pass through.
What happens if you were to place a dilute solution that is in a bag made of a semipermeable membrane and were to then suspend it in a very concentrated solution? A) The size of the suspended bag would decrease. B) The size of the suspended bag would increase. C) The size of the bag would not change. D) The solutions would eventually reach the same concentration.
A) The size of the suspended bag would decrease.
What happens when the molecule-to-molecule attractions in the solute are comparable to those in the solvent? A) The solute can have infinite solubility in the solvent. B) The solute does not dissolve in the solvent. C) The material has only limited solubility in the solvent. D) The solution will become saturated.
A) The solute can have infinite solubility in the solvent.
What do chicken noodle soup and garden soil have in common? A) They are both examples of heterogeneous mixtures. B) They both contain elements. C) They are both examples of compounds. D) nothing
A) They are both examples of heterogeneous mixtures.
Which has the most atoms? A) a mole of gold B) a mole of helium C) a mole of lead D) All of the above have the same number of atoms.
D) All of the above have the same number of atoms: A) a mole of gold B) a mole of helium C) a mole of lead
Why isn't distillation used commercially to purify water? A) Water requires large amounts of energy to boil affordably. B) Bacteria are not killed during the distillation process. C) Odd smelling contaminants boil at lower temperatures than water and so are impossible to remove. D) Distillation does not remove suspended particles such as dirt and humus.
A) Water requires large amounts of energy to boil affordably
Allowing water to cascade or bubble in a fountain during the purification process is an example of ________. A) a gas dissolving in a liquid B) a chemical reaction C) ion exchange D) a solid dissolving in a liquid
A) a gas dissolving in a liquid
Water being purified using aluminum salts and a base is an example of ________. A) a physical separation B) a chemical reaction C) an acid-base reaction D) a chemical separation
A) a physical separation
Which of the following would cost the least to purify by reverse osmosis? A) agricultural runoff B) sea water C) brackish water D) All of the above are the same.
A) agricultural runoff
Which of the following is a pure substance? A) baking soda B) salt water C) cooking oil D) duct tape E) orange juice
A) baking soda
What is the first step in treating raw sewage? A) filtration of solids B) removal of fine particles by settling C) removal of grit by settling D) removal of sludge E) disinfection
A) filtration of solids
If you filter sea water to remove all of the particles you would be left with a clear ________. A) homogeneous mixture called a solution B) homogeneous mixture called a suspension C) heterogeneous mixture called a solution D) heterogeneous mixture called a suspension E) pure liquid
A) homogeneous mixture called a solution
A sample of steel is composed of 5 percent carbon and 95 percent iron. Which is the solvent? A) iron B) carbon
A) iron
In a solution of 77 percent nitrogen and 23 percent oxygen, which is the solvent? A) nitrogen B) oxygen
A) nitrogen
Which of the following best describes a two-molar sucrose solution? A) one liter of solution that contains 2 moles of sucrose B) one liter of solution that contains 2 moles of water C) one liter of solution that contains 6.02 × 1023 molecules of sucrose D) two liters of solution that contains 1 mole of sucrose E) one mole of sucrose dissolved in 2 liters of solution
A) one liter of solution that contains 2 moles of sucrose
Which of the following solutions is the most dilute? A) one liter of water with 1 gram of sugar B) one liter of water with 2 grams of sugar C) one liter of water with 5 grams of sugar D) one liter of water with 10 grams of sugar
A) one liter of water with 1 gram of sugar
Which of the following would be considered a heterogeneous mixture? A) salad dressing B) water C) milk D) vegetable oil E) vinegar
A) salad dressing
In a solution made from one teaspoon of sugar and one liter of water, which is the solute? A) sugar B) water
A) sugar
What is molarity? A) the number of moles of solute per liter of solution B) the number of grams of solute per liter of solution C) the number of moles of solute per liter of solvent D) the number of liters of solute per mole of solution
A) the number of moles of solute per liter of solution
Which of the following would be considered a homogeneous mixture? A) wine B) hydrogen cyanide C) rusty iron D) pretzel E) sugar
A) wine
How is the solubility of a gas affected by temperature? A) As temperature goes up, the solubility goes up. B) As temperature goes up, the solubility goes down.
B) As temperature goes up, the solubility goes down.
Which of the following describes the term concentration? A) It is what you are doing now to answer this question. B) It is the amount of solute in a given amount of solution. C) It is the amount of solvent in a given amount of solution. D) It is the given amount of solution in a given container. E) It is the given amount of solvent per amount of solute.
B) It is the amount of solute in a given amount of solution.
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? A) The size of the suspended bag would decrease. B) The size of the suspended bag would increase. C) The size of the bag would not change. D) The solutions would eventually reach the same concentration.
B) The size of the suspended bag would increase.
Why might softened water not be good for some one who is trying to reduce their dietary sodium ion intake? A) The potassium used in the softener to replace the calcium and magnesium ions increases the sodium retention in the body. B) Water softeners work by replacing the calcium and magnesium ions of the water with sodium ions; softened water contains increased levels of sodium ions. C) The softened water leaches sodium from the body, so a person might not be getting the dietary recommended levels of sodium. D) A person needs a certain level of calcium and magnesium in the water to help excrete the sodium from their body.
B) Water softeners work by replacing the calcium and magnesium ions of the water with sodium ions; softened water contains increased levels of sodium ions.
Treating water with chlorine or ozone during water purification is an example of ________. A) a physical change B) a chemical reaction C) ion exchange D) a solid dissolving in a liquid
B) a chemical reaction
Is the air in your house a homogeneous or heterogeneous mixture? A) homogeneous because it is mixed very well B) heterogeneous because of the dust particles it contains C) homogeneous because it is all at the same temperature D) heterogeneous because it consists of different types of molecules
B) heterogeneous because of the dust particles it contains
Under which of the following conditions would you expect the highest solubility of oxygen gas in water? A) high temperature and low O2 pressure above the solution B) low temperature and high O2 pressure above the solution C) low temperature and low O2 pressure above the solution D) high temperature and high O2 pressure above the solution E) The O2 solubility is independent of temperature and pressure.
B) low temperature and high O2 pressure above the solution
How does a suspension differ from a solution? A) A suspension is a heterogeneous mixture whose components can be separated by simple filtration. A solution is a homogeneous mixture which cannot be separated by simple filtration. B) A suspension is a heterogeneous mixture consisting of different phases whereas a solution is a homogeneous mixture consisting of a single phase. C) Although a solution and suspension are both homogeneous mixtures, only the components of a suspension will separate by spinning the mixture in a centrifuge. D) The difference between a suspension and a solution can only be determined by chemical means.
C) Although a solution and suspension are both homogeneous mixtures, only the components of a suspension will separate by spinning the mixture in a centrifuge.
How can you tell whether a sugar solution is saturated or not? A) Add more sugar, if it dissolves, it is saturated. B) There will be a precipitate if the water is heated. C) Cool the solution to see if there is a precipitate. D) As long as there are more water molecules than sugar molecules, there is a saturated solution.
C) Cool the solution to see if there is a precipitate
Does the concentration of chlorine in drinking water tend to increase or decrease as it leaves the water treatment plant and disperses into the community? Why? A) Increases. As the chlorine reacts with the bacteria in the water, more chlorine is produced. B) Increases. As the water evaporates the chlorine concentration would increase in the remaining water. C) Decreases. Evaporative processes and reaction with organic bacteria would decrease the chlorine concentration. D) Neither. The chlorine concentration in the water does not vary as the water is dispersed into the community.
C) Decreases. Evaporative processes and reaction with organic bacteria would decrease the chlorine concentration.
Phosphate ions, PO43-, were once added to detergents to assist in cleaning. What function did they serve? A) Phosphate ions were relatively good at removing grease by binding with large nonpolar molecules. B) Phosphate ions were large enough to bind with the large grime molecules and remove them. C) Phosphate ions would bind to and remove calcium ions, thus acting as a water softening agent. D) Phosphate ions would reduce the growth of algae in aquatic habitats receiving the waste water.
C) Phosphate ions would bind to and remove calcium ions, thus acting as a water softening agent.
How necessary is soap for removing salt from your hands? A) Soap is necessary because it has both a polar and nonpolar end to interact with the positive and negative ions in the salt. B) 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. C) 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. D) Soap is not necessary because there are no electrical charges on the skin of your hands for the salt to interact with.
C) 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.
Describe what usually happens to a hot solution that is saturated with a solid as it cools. A) The solid that is dissolved comes out of the solution completely. B) The solid stays in the solution. C) Some of the solid comes out of the solution. D) The solution freezes. E) The solution solidifies.
C) Some of the solid comes out of the solution
Why do hot water heaters lose their efficiency quicker in households with hard water? A) The hard water calcium and magnesium ions corrode the heating element. B) The hard water calcium carbonate deposits oxidize the inner tank wall. C) The calcium carbonate on the inner surface of the hot water tank builds up to the point that it insulates the water from the heating element. D) The hard water calcium ions exchange with iron ions from the inner metal wall which react with the water heater base to form rust and deteriorate the bottom of the tank.
C) The calcium carbonate on the inner surface of the hot water tank builds up to the point that it insulates the water from the heating element.
What can be said about drinking water that is 99.9999 percent free of some poison, such as a pesticide? A) In each 10,000 parts of the contaminated water there is one part pesticide and 9999 parts pure water. B) In each 100,000 parts of the contaminated water there is one part pesticide and 99,999 parts pure water. C) The ratio of water molecules to pesticide molecules in the glass is so great that drinking the water is not problematic. D) The water is highly contaminated and surely not fit to drink.
C) The ratio of water molecules to pesticide molecules in the glass is so great that drinking the water is not problematic.
Many dry cereals are fortified with iron, which is added to the cereal in the form of small iron particles. How might these particles be separated from the cereal? A) add water and the iron particles will float to the top B) blend the cereal to a fine consistency and pass through a filter C) collect the iron filings with a magnet D) heat the cereal so that the iron particles melt and thereby coalesce
C) collect the iron filings with a magnet
Why does oxygen have such a low solubility in water? A) Water's attraction for itself is stronger than its attraction for oxygen molecules. B) Water and oxygen only attract one another by means of weak dipole-induced dipole attractions. C) The hydrogen bonding in water keeps the oxygen solubility low. D) Both A and B are true.
D) Both A and B are true: A) Water's attraction for itself is stronger than its attraction for oxygen molecules. B) Water and oxygen only attract one another by means of weak dipole-induced dipole attractions
Someone argues that he or she doesn't drink tap water because it contains thousands of molecules of some impurity in each glass. How would you respond in defense of the water's purity, if it indeed does contain thousands of molecules of some impurity per glass? A) Impurities aren't necessarily bad, in fact, they may be good for you. B) The water contains water molecules and each water molecule is pure. C) There's no defense. If the water contains impurities it should not be drunk. D) Compared to the billions and billions of water molecules, a thousand molecules of something else is practically nothing.
D) Compared to the billions and billions of water molecules, a thousand molecules of something else is practically nothing.
What statement best describes a "mole" as used by chemists? A) a little furry mammal that lives in the ground B) a very small number chemists use to count atoms or molecules C) the amount of molecules or atoms in 1 gram of something D) It is a very large number chemists use to count atoms or molecules
D) It is a very large number chemists use to count atoms or molecules
Suggest why sodium chloride, NaCl, is insoluble in gasoline. Consider the electrical attractions. A) Since this molecule is so small, there is not much opportunity for the gasoline to interact with it through any electrical attractions. B) 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. C) Since gasoline is so strongly attracted to itself, the salt, NaCl is excluded. D) Salt is composed of ions that are too attracted to themselves. Gasoline is non-polar so salt and gasoline will not interact very well.
D) Salt is composed of ions that are too attracted to themselves. Gasoline is non-polar so salt and gasoline will not interact very well.
Fish don't live very long in water that has just been boiled and brought back to room temperature. Suggest why. A) There is now a higher concentration of dissolved CO2 in the water. B) The nutrients in the water have been destroyed. C) Since some of the water was evaporated while boiling, the salts in the water are now more concentrated. This has a negative effect on the fish. D) The boiling process removes the air that was dissolved in the water. Upon cooling the water is void of its usual air content, hence, the fish drown.
D) The boiling process removes the air that was dissolved in the water. Upon cooling the water is void of its usual air content, hence, the fish drown.
What is the difference between a compound and a mixture? A) They both consist of atoms from different elements. B) The way in which their atoms are bonded together. C) One is a solid and the other is a liquid. D) The components of a mixture are not chemically bonded together.
D) The components of a mixture are not chemically bonded together.
Why is it important to conserve fresh water? A) There is little fresh water available to us on our planet. B) As the human population grows, so does our need for fresh water. C) It is expensive to purify nonpotable water. D) all of the above
D) all of the above: A) There is little fresh water available to us on our planet. B) As the human population grows, so does our need for fresh water. C) It is expensive to purify nonpotable water.
Which of the following statements describes a saturated solution? A) a solution where the solvent cannot dissolve any more solute B) a solution of salt water with salt at the bottom C) a carbonated beverage with bubbles D) all of the above
D) all of the above: A) a solution where the solvent cannot dissolve any more solute B) a solution of salt water with salt at the bottom C) a carbonated beverage with bubbles
Which of the following solutions is the most concentrated? A) one liter of water with 1 gram of sugar B) one liter of water with 2 grams of sugar C) one liter of water with 5 grams of sugar D) one liter of water with 10 grams of sugar
D) one liter of water with 10 grams of sugar
Which of the following statements does not describes the similarity between soaps and detergents? A) They have a polar ionic end and a long nonpolar tail. B) Both dissolve oils. C) Both are synthetic. D) Both are biodegradable. E) Both are made from fatty acids.
E) Both are made from fatty acids
Which of the following solutions is the most dilute? A) 0.1 liter of water with 1 gram of sugar B) 0.2 liter of water with 2 grams of sugar C) 0.5 liter of water with 5 grams of sugar D) 1 liter of water with 10 grams of sugar E) They all have the same concentration.
E) They all have the same concentration: A) 0.1 liter of water with 1 gram of sugar B) 0.2 liter of water with 2 grams of sugar C) 0.5 liter of water with 5 grams of sugar D) 1 liter of water with 10 grams of sugar