Physic

Q: Phosphate ions, 3-, 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 wastewater.

Q: Fatty acid molecules can align to form a barrier called a bilipid layer, shown below. In this schematic, the ionic end of the fatty acid is shown as a circle and the nonpolar chain is shown as a squiggly line. From the schematic above: why do nonpolar molecules have a difficult time passing through the bilipid layer? A) The nonpolar molecules are too large for the space through which they need to pass. B) The nonpolar molecules are repelled by the polar water molecules. C) The nonpolar molecules have a difficult time getting past the ionic heads of the fatty acid molecules, which are surrounded by water molecules. D) Nonpolar molecules tend to bind with the bilipid layer, thus inhibiting their passage.

Q: 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.

Q: 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.

Q: What is the main difference between a soap and a detergent? A) Soaps are made from fatty acids, detergents are synthetic. B) Soaps are biodegradable, detergents are not. C) Detergents are better than soaps. D) Soaps are all natural. E) Soaps and detergents are exactly the same.

Q: Which of the above might best describe how soap behaves in a nonpolar solvent like turpentine? A) a B) b C) c D) d E) none of the above

Q: Which of the above would best describe how soap behaves in water? A) a B) b C) c D) d E) none of the above

Q: Which of the following picture might best describe a soap or detergent? A) a B) b C) c D) d E) none of the above

Q: Why might a solvent like turpentine be better for removing grease and grime than water? A) Like dissolves like. B) Oil and grease have similar interatomic forces as the turpentine and so are more soluble. C) Water is too polar and doesn't interact well with the nonpolar oils. D) Oil and grease have very limited solubility in the water. E) all of the above

Q: 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 C 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.

Q: When you set a pot of tap water on the stove to boil, you'll often see bubbles start to form well before boiling temperature is ever reached. Explain this observation. A) These are dissolved salts heating up and escaping from the water. B) These bubbles are formed as the surrounding gases from the air dissolve into the water as it is heated. C) They are very minute pockets of water in the gaseous phase. When they get large enough, the water will boil as this gas escapes. D) These initial bubbles are the gases that were dissolved in the water coming out of solution. The solubility of gases in water decreases with increasing temperature.

Q: Account for the observation that ethyl alcohol, OH, dissolves readily in water but dimethyl ether, COC, which has the same number and kinds of atoms, does not. A) The hydrogens on the dimethyl ether surround the molecule, shielding the inner atoms from interacting with the water. B) Because the carbons arrange themselves in a straight line, the ethanol can interact more easily with more water molecules, thus increasing its solubility. C) The high electronegativity of the carbon-oxygen-carbon bond on dimethyl ether creates a strong dipole charge on the ends of the molecule, making it highly soluble in water. D) Because dimethyl ether lacks an -OH group, it is significantly less polar than is ethyl alcohol and is not readily soluble in water.

Q: Would you expect to find more dissolved oxygen in polar or tropical ocean waters? Why? A) There would be more dissolved oxygen in the tropical oceans because intense tropical storms mix up the atmospheric oxygen into the ocean water. B) There would be more dissolved oxygen in the polar oceans because the colder oxygen would "sink" and dissolve into the water. C) There would be more dissolved oxygen in the tropical oceans because the heated oxygen molecules in the air would collide with and mix into the water. D) There would be more dissolved oxygen in the polar oceans because the solubility of oxygen in water decreases with increasing temperature.

Q: Hydrogen chloride, HCl, is a gas at room temperature. Would you expect this material to be very soluble or not very soluble in water? A) HCl is very soluble in water by virtue of the dipole/dipole attractions occurring between the HCl and O molecules. B) It is not very soluble because it is a gas, and all gases have very low solubility in water at room temperature. C) HCl is very soluble in water because it is such a small molecule, there is little electrical attraction to other HCl molecules. D) It is not very soluble because as a gas with low density, it floats to the surface of the water and then into the surrounding atmosphere.

Q: Deuterium oxide, O, and water, O, have the same chemical structure and differ only in that O possesses the deuterium isotope of hydrogen, whereas water possesses the protium isotope. Deuterium oxide, also known as "heavy water," is 11 percent heavier than water. Might you expect its boiling temperature also to be about 11 percent greater? Why or why not? A) The mass of the molecules has a far greater influence on the boiling temperature of the substance than does the polarity of the molecules, so O boils at a higher temperature. B) Since they have the same chemical structures, there is a similar molecular attraction between the molecules, so their boiling temperatures are similar. C) Since deuterium is radioactive, it breaks down more easily, so it has a lower boiling temperature than water. D) Since boiling temperature is a measure of the speed of a molecule, the heavier molecules move slower and thus have a higher boiling temperature.

Q: 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.

Q: Which solute graphed above has a solubility in water that does not markedly increase with increasing temperature? A) NaN B) LiCl C) KCl D) NaCl

Q: 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.

Q: Why are noble gases infinitely soluble in noble gases? A) The noble gases are attracted to each other by induced dipole-induced dipole attractions, but there is only one attraction per molecule. B) These are the smallest atoms on the periodic table. C) The molecules do not interact with each other, excluding other molecules. D) Noble gases can be mixed homogeneously in any proportion.

Q: 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 the surface too rapidly, the excessive nitrogen bubbles out of the bodily fluidsmuch 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? A) Oxygen and helium have stronger attractions for each other than they do for the blood, so less helium will be dissolved in the blood and to cause the bends. B) 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. C) The nitrogen in the blood will bind to helium, and so will be exhaled rather than being stuck in the blood. D) Helium is a smaller molecule than nitrogen, so when it bubbles out of solution, it is less painful and less harmful to the body.

Q: If nitrogen, , were pumped into your lungs at high pressure, what would happen to its solubility in your blood stream? A) The greater the pressure, the greater the solubility. B) The greater the pressure, the lower the solubility. C) You cannot change solubility of a substance by changing the pressure. D) Nitrogen is not soluble in your blood.

Q: Based on atomic size, which would you expect to be more soluble in water: helium, He, or nitrogen, ? A) Although He is smaller, its outer orbital is filled and the atom will have little attraction to the water molecules. B) Since He atoms are smaller, more of them can fit into solution, so it has a higher solubility in water. C) Nitrogen atoms are bigger and so nitrogen molecules should be more soluble in water due to greater dipole-induced dipole attractions. D) He atoms are bigger and so helium molecules should be more soluble in water due to greater dipole-induced dipole attractions.

Q: 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.

Q: Under which of the following conditions would you expect the highestsolubility of oxygen gas in water? A) high temperature and low pressure above the solution B) low temperature and high pressure above the solution C) low temperature and low pressure above the solution D) high temperature and high pressure above the solution E) The solubility is independent of temperature and pressure.

Q: 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.

Q: What property primarily determines the effect of temperature on the solubility of gas molecules? A) the kinetic energy of the gas B) the polarity of the gas C) the molecular weight of the gas D) the ionic strength of the gas E) the dipole strength of the solvent

Q: 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? A) 20 g B) 10 g C) 0 g D) 30 g E) 33 g

Q: If the solubility of a compound is 72 grams per liter, how many grams of the compound will dissolve in 0.50 liters? A) 36 g B) 72 g C) 144 g D) 30 g E) none of the above

Q: A solid has a solubility at room temperature of 78 grams per liter. If 1.0 L of a hot solution containing 100. g of solute is cooled to room temperature, how much solid is formed? A) 22 g B) 100 g C) 78 g D) 1 L E) 78g/L

Q: 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.

Q: How is the solubility of a gas affected by temperature? A) As temperature goes up, the solubility goes up. B) As temperature goes down, the solubility goes down. C) As temperature goes up, the solubility stays the same. D) As temperature goes down, the solubility goes up. E) both A and B

Q: How is the solubility of a solid affected by temperature? A) As temperature goes up, the solubility goes up. B) As temperature goes down, the solubility goes down. C) As temperature goes up, the solubility goes down. D) As temperature goes down, the solubility goes up. E) both A and B

Q: Which of the following might have the lowest solubility in water? A) CH3OH B) Cl2 C) O2 D) CH3CH3 E) none of the above

Q: Which of the following might have the best solubility in water? A) CH3OH B) Cl2 C) O2 D) CH3CH3 E) none of the above

Q: 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. E) none of the above

Q: 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. E) none of the above

Q: How many moles of water are there in 100. grams of water? A) 1800 moles B) 100 moles C) 0.018 moles D) 5.55 moles

Q: How many moles of sugar, C12H22O11, are there in 200. grams? A) 0.585 moles B) 68,400 moles C) 1.71 moles D) 0.684 moles

Q: What is the sum of the atomic masses of all the atoms in sucrose, ? A) 342 amu B) 182 amu C) 270 amu D) none of the above

Q: A student is told to use 20.0 grams of sodium chloride to make an aqueous solution that has a concentration of 10.0 grams of sodium chloride per liter of solution. Assuming that 20.0 grams of sodium chloride has a volume of 7.5 milliliters, about how much water will she use in making this solution? A) 9.25 L B) 9.5 L C) 9.9925 L D) 10 L

Q: What is the molarity when water is added to 2 moles of sodium chloride to make 0.5 liter of solution? A) 8 M B) 4 M C) 5 M D) 2.5 M

Q: How many grams of sodium chloride are needed to make 15 L of a solution that has a concentration of 3.0 g per liter of solution? A) 30 g B) 141 g C) 5 g D) 45 g

Q: How many grams of sugar (sucrose) are there in 5 liters of sugar water that has a concentration of 0.5 grams per liter of solution? A) 50 g B) 25 g C) 2.5 g D) 1.5 g

Q: 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.

Q: Which of the following solutions is the most concentrated? A) 0.5 L of a 3 molar solution B) 3.0 L of a 0.5 molar solution C) 2.0 L of a 1 molar solution D) 0.5 L of a 1 molar solution E) 2.0 L of a 2 molar solution

Q: What is the molarity of 0.5 liters of a solution with five moles of sucrose in it? A) 10 molar B) 0.5 molar C) 5 molar D) 2.5 molar E) 1 molar

Q: If you need 3.01 1023 molecules of sucrose, how many liters of a 4.00 molar solution would you need? A) 0.125 L B) 0.250 L C) 4.00 L D) 1.00 L E) none of the above

Q: If you need 10 moles of sucrose, how many liters of a 4.0 molar solution would you need? A) 2.5 L B) 0.25 L C) 25 L D) 10. L E) none of the above

Q: How many molecules of sucrose are in 0.5 L of a 2 molar solution of sucrose? A) 3.01 1023 molecules of sucrose B) 6.02 1023 molecules of sucrose C) 12.04 1023 molecules of sucrose D) 0.5 E) 1 gram

Q: How many molecules of sucrose are in 0.5 L of a 1 molar solution of sucrose? A) 3.01 1023 molecules of sucrose B) 6.02 1023 molecules of sucrose C) 12.04 1023 molecules of sucrose D) 0.5 E) 1 gram

Q: How many molecules of sucrose are in a 0.5 moles of sucrose? A) 3.01 1023 molecules of sucrose B) 6.02 1023 molecules of sucrose C) 12.04 1023 molecules of sucrose D) 0.5 E) 1 gram

Q: 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

Q: 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 E) none of the above

Q: What statement best describes a mole? 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. E) none of the above

Q: 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. E) none of the above

Q: Which of the following solutions is the most concentrated? A) 0.1 liter of water with 1 gram of sugar B) 2 liters of water with 0.2 gram of sugar C) 0.5 liter of water with 50 grams of sugar D) 3 liters of water with 30 grams of sugar E) They all have the same concentration.

Q: 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.

Q: 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 E) They all have the same volume.

Q: 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 E) They all have the same volume.

Q: 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 E) none of the above

Q: 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.

Q: A sample of steel is composed of 5 percent carbon and 95 percent iron. Which is the solvent? A) iron B) carbon C) steel D) Steel is not a solution, it is a mixture. E) A solid cannot be a solvent.

Q: In a solution of 77 percent nitrogen and 23 percent oxygen, which is the solvent? A) nitrogen B) oxygen C) both D) neither E) Gases cannot form solutions.

Q: In a solution made from one teaspoon of sugar and one liter of water, which is the solute? A) sugar B) water C) the teaspoon D) both sugar and water E) none of the above

Q: Which of the following material phases cannot form a solution? A) solids B) liquids C) gases D) All of the above can form solutions. E) None of the above can form solutions.

Q: 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

Q: Which of the following boxes represents a suspension?A) Only A represents a suspension.B) Only B represents a suspension.C) Only C represents a suspension.D) Each of these could represent a submicroscopic portion of a suspension.

Q: 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.

Q: Classify the following as element, compound, or mixture, and justify your classifications: table salt, stainless steel, table sugar, aluminum, ice. A) mixture; element; compound; element; element B) compound; mixture; compound element; compound C) mixture; compound; mixture; element; compound D) compound; element; compound; element; compound

Q: 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

Q: 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.

Q: Read carefully. Twice as much as one million trillion is two million trillion. One thousand times as much is 1000 million trillion. One million times as much is 1,000,000 million trillion, which is the same as one trillion trillion. Thus, one trillion trillion is a million times greater than a million trillion. Got that? So how many more water molecules than impurity molecules are there in a glass of water that is 99.9999 percent pure?A) 1000 (one thousand: 1 x ) more water molecules than impurities moleculesB) 1,000,000 (one million: 1 x) more water molecules than impurities moleculesC) 1,000,000,000 (one billion: 1 x ) more water molecules than impurities moleculesD) 1,000,000,000,000,000,000 (one million trillion: 1 x ) more water molecules than impurities molecules

Q: 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.

Q: A sample of water that is 99.9999 percent pure contains 0.0001 percent impurities. Consider from Chapter 1 that a glass of water contains on the order of a trillion trillion (1x ) molecules. If 0.0001 percent of these molecules were the molecules of some impurity, about how many impurity molecules would this be?A) 1000 (one thousand: 1 x )B) 1,000,000 (one million: 1 x)C) 1,000,000,000 (one billion: 1 x)D) 1,000,000,000,000,000,000 (one million trillion: 1 x )

Q: How would you classify the following material? a cappuccino (with foam) A) a suspension B) a heterogeneous mixture C) a solution D) an element E) a compound

Q: How would you classify the following material? coffee (with milk) A) a suspension B) a heterogeneous mixture C) a solution D) an element E) a compound

Q: How would you classify the following material? coffee (black) A) a suspension B) a heterogeneous mixture C) a solution D) an element E) a compound

Q: How would you classify the following material? milk A) a suspension B) a heterogeneous mixture C) a solution D) an element E) a compound

Q: When blue food coloring is stirred into water, the result is a 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.

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