Question 1

Why might sodium carbonate (washing soda,Na2CO3)be added to hard water to aid in cleaning?

Accepted Answer

A) The hard ions in the water are more attracted to the carbonate ions -2 charge. 
B) The hard ions are dissolved by the added sodium ions. 
C) The soap gets softer due to the added ions. 
D) The ions solubilize the soap due to ion-ion intermolecular attraction,which improves the cleaning ability. 
E) none of the above 
A) The hard ions in the water are more attracted to the carbonate ions -2 charge. 
B) The hard ions are dissolved by the added sodium ions. 
C) The soap gets softer due to the added ions. 
D) The ions solubilize the soap due to ion-ion intermolecular attraction,which improves the cleaning ability. 
E) none of the above

Question 2

Why can't the elements of a compound be separated from one another by physical means?

Accepted Answer

A) They are too homogeneous when found within a compound. 
B) Their atoms are too tightly bound to one another. 
C) Elements found within a compound tend to be inert. 
D) Elements tend not to be soluble in water. 
A) They are too homogeneous when found within a compound. 
B) Their atoms are too tightly bound to one another. 
C) Elements found within a compound tend to be inert. 
D) Elements tend not to be soluble in water.

Question 3

Mixtures can be separated into their components by taking advantage of differences in the chemical properties of the components.Why might this separation method be less convenient than taking advantage of differences in the physical properties of the components?

Accepted Answer

A) A chemical property involves a chemical change so that you no longer have what you had. 
B) Chemical properties are not as apparent as are physical properties. 
C) The chemical properties of the components of a mixture are too similar to each other. 
D) The chemical properties of the components of a mixture are too different from each other. 
A) A chemical property involves a chemical change so that you no longer have what you had. 
B) Chemical properties are not as apparent as are physical properties. 
C) The chemical properties of the components of a mixture are too similar to each other. 
D) The chemical properties of the components of a mixture are too different from each other.

Question 4

How many molecules of sucrose are in a 0.5 moles of sucrose?

Accepted Answer

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 
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

Question 5

Which of the following statements about desalinization is untrue?

Accepted Answer

A) You can use osmosis to remove salt from saltwater. 
B) You can use distillation to separate salt from saltwater. 
C) Desalinization is an energy intensive process. 
D) All are untrue. 
E) Only a and b are untrue. 
A) You can use osmosis to remove salt from saltwater. 
B) You can use distillation to separate salt from saltwater. 
C) Desalinization is an energy intensive process. 
D) All are untrue. 
E) Only a and b are untrue.

Question 6

Under which of the following conditions would you expect the highest solubility of oxygen gas in water?

Accepted Answer

A) high temperature and low O2pressure 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 
A) high temperature and low O2pressure 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

Question 7

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?

Accepted Answer

A) 9.25 L 
B) 9.5 L 
C) 9.9925 L 
D) 10 L 
A) 9.25 L 
B) 9.5 L 
C) 9.9925 L 
D) 10 L

Question 8

Why isn't distillation used commercially to purify water?

Accepted Answer

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. 
E) none of the above 
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. 
E) none of the above

Question 9

Which of the following solutions is the most dilute?

Accepted Answer

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. 
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.

Question 10

Fatty acid molecules can also align to form a bilipid layer that extends in 3-dimensions.Shown below is a cross section of this structure.What is this structure called? (Hint: it forms the basis of all life.)

Accepted Answer

A) DNA 
B) a nucleoside 
C) a cell 
D) a gene 
A) DNA 
B) a nucleoside 
C) a cell 
D) a gene

Question 11

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?

Accepted Answer

A) 22 g 
B) 100 g 
C) 78 g 
D) 1 L 
E) 78g/L 
A) 22 g 
B) 100 g 
C) 78 g 
D) 1 L 
E) 78g/L

Question 12

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 (1 × $10 ^ { 24 }$ )molecules.If 0.0001 percent of these molecules were the molecules of some impurity,about how many impurity molecules would this be?

Accepted Answer

A) 1000 (one thousand: 1 × $10 ^ { 3 }$ ) 
B) 1,000,000 (one million: 1 × $10 ^ { 6 }$ ) 
C) 1,000,000,000 (one billion: 1 × $10 ^ { 9 }$ ) 
D) 1,000,000,000,000,000,000 (one million trillion: 1 × $10 ^ { 18 }$ 
A) 1000 (one thousand: 1 × $10 ^ { 3 }$ ) 
B) 1,000,000 (one million: 1 × $10 ^ { 6 }$ ) 
C) 1,000,000,000 (one billion: 1 × $10 ^ { 9 }$ ) 
D) 1,000,000,000,000,000,000 (one million trillion: 1 × $10 ^ { 18 }$

Question 13

Hydrogen chloride,HCl,is a gas at room temperature.Would you expect this material to be very soluble or not very soluble in water?

Accepted Answer

A) HCl is very soluble in water by virtue of the dipole/dipole attractions occurring between the HCl and $\mathrm { H } _ { 2 }$ 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. 
A) HCl is very soluble in water by virtue of the dipole/dipole attractions occurring between the HCl and $\mathrm { H } _ { 2 }$ 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.

Question 14

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?

Accepted Answer

A) 30 g 
B) 141 g 
C) 5 g 
D) 45 g 
A) 30 g 
B) 141 g 
C) 5 g 
D) 45 g

Question 15

What is the difference between a compound and a mixture?

Accepted Answer

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. 
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.

Question 16

Why might softened water not be good for some one who is trying to reduce their dietary sodium ion intake?

Accepted Answer

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. 
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.

Question 17

Why does oxygen have such a low solubility in water?

Accepted Answer

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. 
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.

Question 18

If you were to increase the pressure of a gas above a liquid (such as by pressing a piston above a liquid)what happens?

Accepted Answer

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. 
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.

Question 19

In a solution of 77 percent nitrogen and 23 percent oxygen,which is the solvent?

Accepted Answer

A) nitrogen 
B) oxygen 
C) both 
D) neither 
E) Gases cannot form solutions. 
A) nitrogen 
B) oxygen 
C) both 
D) neither 
E) Gases cannot form solutions.

Question 20

Classify the following as element,compound,or mixture,and justify your classifications: table salt,stainless steel,table sugar,aluminum,ice.

Accepted Answer

A) mixture; element; compound; element; element 
B) compound; mixture; compound element; compound 
C) mixture; compound; mixture; element; compound 
D) compound; element; compound; element; compound 
A) mixture; element; compound; element; element 
B) compound; mixture; compound element; compound 
C) mixture; compound; mixture; element; compound 
D) compound; element; compound; element; compound

Exam 16: Mixtures

Why might sodium carbonate (washing soda,Na2CO3)be added to hard water to aid in cleaning?

Why can't the elements of a compound be separated from one another by physical means?

Mixtures can be separated into their components by taking advantage of differences in the chemical properties of the components.Why might this separation method be less convenient than taking advantage of differences in the physical properties of the components?

How many molecules of sucrose are in a 0.5 moles of sucrose?

Which of the following statements about desalinization is untrue?

Under which of the following conditions would you expect the highest solubility of oxygen gas in water?

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?

Why isn't distillation used commercially to purify water?

Which of the following solutions is the most dilute?

Fatty acid molecules can also align to form a bilipid layer that extends in 3-dimensions.Shown below is a cross section of this structure.What is this structure called? (Hint: it forms the basis of all life.)

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?

Hydrogen chloride,HCl,is a gas at room temperature.Would you expect this material to be very soluble or not very soluble in water?

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?

What is the difference between a compound and a mixture?

Why might softened water not be good for some one who is trying to reduce their dietary sodium ion intake?

Why does oxygen have such a low solubility in water?

If you were to increase the pressure of a gas above a liquid (such as by pressing a piston above a liquid)what happens?

In a solution of 77 percent nitrogen and 23 percent oxygen,which is the solvent?

Classify the following as element,compound,or mixture,and justify your classifications: table salt,stainless steel,table sugar,aluminum,ice.

Patterns of Motion and Equilibrium

Newtons Laws of Motion

Momentum and Energy

Gravity, Projectiles, and Satellites

Fluid Mechanics

Thermal Energy and Thermodynamics

Heat Transfer and Change of Phase

Static and Current Electricity

Magnetism and Electromagnetic Induction

Waves and Sound

Light

Atoms and the Periodic Table

The Atomic Nucleus and Radioactivity

Elements of Chemistry

How Atoms Bond and Molecules Attract

How Chemicals React

Two Classes of Chemical Reactions

Organic Compounds

Rocks and Minerals

Plate Tectonics and Earths Interior

Shaping Earths Surface

Geologic Time - Reading the Rock Record

The Oceans, Atmosphere, and Climatic Effects

Driving Forces of Weather

The Solar System

Stars and Galaxies

The Structure of Space and Time

Prologue: The Nature of Science

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Why might sodium carbonate (washing soda,Na₂CO₃)be added to hard water to aid in cleaning?