Bio 264 : Practice Quiz M02:10-14- M.03

A solution at pH 6 contains ____ than the same amount of solution at pH 8. 1) 2 times more H+ 2) 4 times more H+ 3) 100 times more H+ 4) 4 times less H+ 5) 100 times less H+

3

The osmolarity of a solution is _________.

A) a measure of solute concentration.

What is a mole?

D) all of the above

Which of the following statements is true about acid precipitation? (eText Concept 3.3)

It washes away some minerals that are plant nutrients, and causes some toxic minerals to accumulate.

Imagine that organisms consisted of 70-95% alcohol instead of 70-95% water. Alcohol's specific heat is about half that of water. How would living things be different? (eText Concept 3.2)

Systems for temperature regulation would have to be much more efficient.

What do cohesion, surface tension, and adhesion have in common with reference to water?

The extraordinary qualities of water are emergent properties resulting from hydrogen bonding.

How does water help to maintain the body's temperature even when the weather is cold? As water molecules slow down they form more hydrogen bonds and release energy. When the body experiences a large drop in temperature it forces the water molecules to move faster in order to break hydrogen bonds and release energy as heat. As the temperature decreases the water molecules lose kinetic energy, this allows them to form more stable polar covalent bonds. Since water has a high heat capacity it retains heat longer. a, c, d b, c, d a and c a and d

a and d

Surface tension involves _____.

cohesion

Which action would involve the greatest transfer of heat?

condensing 5 g of steam to liquid water

Which action would involve the greatest transfer of heat? (eText Concept 3.2)

condensing 5 g of steam to liquid water

when one or more pairs of valence electrons are shared by two neutral atoms, what type of bond is formed?

covalent bond

Hydrophilic substances, but not hydrophobic substances, _____. (eText Concept 3.2)

have charges and partial charges to which water molecules can adhere

Some substances, such as oil and gasoline, will not dissolve in water because _____.

their molecules have no charges or partial charges to which water molecules can adhere

Some substances, such as oil and gasoline, will not dissolve in water because _____. (eText Concept 3.2)

their molecules have no charges or partial charges to which water molecules can adhere

A mole of ethyl alcohol weighs 46 g. How many grams of ethyl alcohol are needed to produce 1 L of a 2-millimolar (2 mM) solution? (eText Concept 3.2)

0.092 g

A mole of ethyl alcohol weighs 46 grams. How many grams of ethyl alcohol are needed to produce 1 L of a 2-millimolar (2 mM) solution?

0.092 g This would produce a 2-M solution. Remember that "milli-" means thousandth

A molecule that has all nonpolar covalent bonds would be _____. 1) hydrophobic 2) hydrophilic 3) acidic 4) basic (alkaline) 5) ionic

1

Because molecules of water are farther apart in ice than in liquid water, _____. 1) ice floats 2) ice is denser than liquid water 3) ice expands when it melts 4) ice vaporizes before liquid water does 5) all of the above

1

Hydrophilic substances, but not hydrophobic substances, _____. 1) have charges and partial charges to which water molecules can adhere 2) have a higher bond energy than water 3) give up electrons to solvents 4) accept electrons from solvents 5) are repelled by water

1

Pure water has a pH of 7. Why does uncontaminated rainwater have a pH of 5.6? 1) formation of carbonic acid from carbon dioxide and water 2) presence of sulfuric acid 3) presence of nitric acid 4) burning of fossil fuels 5) none of the above

1

The amount of heat required to change the temperature of 1 g of any substance by °C is defined as _____. 1) the specific heat of that substance 2) 1 calorie 3) the heat of vaporization of that substance 4) 1 kilocalorie 5) molecular cohesion

1

The partial charges on a water molecule occur because of _____. 1) the unequal sharing of electrons between the hydrogen and the oxygen atoms of a water molecule 2) the achievement of a stable configuration by one atom of a bond but not by the other partner 3) covalent bonding 4) widespread ionization 5) the high electronegativity of hydrogen

1

The phenomenon responsible for the maintenance of a column of water as it moves upward through a vessel is _____. 1) cohesion 2) adhesion 3) surface tension 4) evaporation 5) heat of vaporization

1

To make a 1% solution of glucose, you would dissolve ____ gram(s) of glucose into enough water to make a 100mL solution. 0.1 1 10 100

1

Water is a polar molecule. This means that _____. 1) the opposite ends of the molecule have opposite electrical charges 2) water molecules are linear, like a pole 3) water is one of the many hydrophobic molecules 4) the atoms in water have equal electronegativities 5) all of the above

1

Water is a very versatile solvent because water molecules are_____. 1) polar 2) nonpolar 3) ionic 4) hydrophobic 5) volatile

1

Water striders are common insects that can skip across the surface of ponds and streams. This lifestyle is enabled by water's _____. 1) cohesion and resulting surface tension 2) high specific heat 3) adhesion 4) none of the above

1

Which of the following statements about water is true? 1. Water participates in Hydrogen bonding. 2. Water is an important element in our bodies. 3. Hydrogen and oxygen in water are held together by an ionic bond. 4. Electrons are shared equally between the hydrogen and oxygen. 1, 2, 3, 4 1, 2, 3 1, 2 1 2, 3, 4

1

Why are cell membranes composed primarily of hydrophobic molecules? 1) In order to perform their function of separating the aqueous solutions outside of cells from the aqueous solutions inside of cells, cell membranes cannot be soluble in water. 2) Cell membranes must be composed of polar molecules in order to interact with the aqueous solutions inside of cells. 3) In order to maintain a proper pH, cell membranes must be hydrophobic. 4) Cell membranes must be hydrophobic in order to form colloids. 5) Cell membranes must be composed of nonpolar molecules in order to form a hydration shell around the cell.

1

You can fill a glass of water to just slightly above the rim without it spilling over the glass. What property of water best explains this phenomenon? 1) surface tension 2) adhesion 3) its polarity 4) evaporative cooling 5) none of the above

1

Which of the following statements about water is true?

1 (1. Water participates in Hydrogen bonding.

When one mole of potassium chloride (KCl) dissolves in water it dissociates into two ions. After the ions dissociate we could say that there is/are __________ mole(s) of K+ in solution and __________ mole(s) of Cl- in solution. ½, ½ 1, 1 2, 2 1, 2

1,1

If you place 2 Osm of NaCl into water, what is the osmolarity of Na+ in water? 0.5 Osm 1.0 Osm 1.5 Osm 2.0 Osm

1.0 Osm

A solution at pH 6 contains _____ than the same amount of solution at pH 8.

100 times more H+

A solution at pH 6 contains _____ than the same amount of solution at pH 8. (eText Concept 3.3)

100 times more H+

A substance that minimizes changes in the concentration of H+ and OH- in a solution is a(n) ______. 1) hydrocarbon 2) buffer 3) NaCl 4) strong acid 5) strong base

2

Adding a base tends to _____ of a solution. 1) lower the hydrogen ion concentration and lower the pH 2) lower the hydrogen ion concentration and increase the pH 3) increase the hydrogen ion concentration and lower the pH 4) increase the hydrogen ion concentration and increase the pH 5) lower the hydroxide ion concentration and lower the pH

2

Adding acid tends to ____ of a solution. 1) increase the hydrogen ion concentration and raise the pH 2) increase the hydrogen ion concentration and lower the pH 3) decrease the hydrogen ion concentration and raise the pH 4) decrease the hydrogen ion concentration and lower the pH 5) either increase or decrease the pH, depending on the original acidity

2

Imagine that organisms consisted of 70-95% alcohol instead of 70-95% water. Alcohol's specific heat is about half that of water. How would living things be different? 1) Organisms would be able to live in a much wider range of temperatures. 2) Systems for temperature regulation would have to be much more efficient. 3) Living organisms would have to be much smaller. 4) Warm-blooded organisms would require less insulation such as fur or feathers. 5) none of the above

2

Most of water's unique features (for example, its versatility as a solvent, ability to moderate temperature, and cohesive behavior) result from the fact that _____. 1) hydrogen is the only element without any neutrons 2) oxygen attracts electrons more than hydrogen does 3) oxygen has only one stable isotope, but hydrogen has three 4) oxygen has two unfilled electron shells 5) More than one of the above is correct.

2

Some substances, such as oil and gasoline, will not dissolve in water because _____. 1) their molecules are so large 2) their molecules have no charges or partial charges to which water molecules can adhere 3) they do not ionize 4) their electrons are so stable that they do not exchange atoms with water molecules 5) oil and gasoline are organic compounds

2

The bonds that are broken when water vaporizes are 1) ionic bonds. 2) hydrogen bonds between water molecules. 3) covalent bonds between atoms within water molecules. 4) polar covalent bonds. 5) nonpolar covalent bonds.

2

Water molecules have _____ than molecules of similar size, such as ammonia and methane. 1) lower specific heat 2) a higher boiling point 3) a lower melting point 4) a lower capacity for forming hydrogen bonds 5) less surface tension

2

Water readily sticks to many other substances, a property called ______. 1) cohesion 2) adhesion 3) polarity 4) hydrophobic bonding

2

Which best describes how charges are distributed on a water molecule? 1) The oxygen end is positive relative to the end with the two hydrogen atoms. 2) The oxygen end is negative relative to the end with the two hydrogen atoms. 3) The charge is neutral and equal throughout the molecule. 4) The oxygen end is neutral; one of the hydrogen atoms has a slight positive charge and the other hydrogen atom has a slight negative charge

2

Which of the following statements is true about acid precipitation? 1) It harms aquatic life, but has little effect on terrestrial life. 2) It washes away some minerals that are plant nutrients, while causing some toxic minerals to accumulate. 3) Automobile use is the leading contributor to acid rain. 4) Industrial areas are hit hardest by acid rain. 5) none of the above

2

A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.) 1) 50°C 2) 5°C 3) 10°C 4) 100°C 5) 1°C

3

How does the polarity of water contribute to its ability to dissolve so many substances? 1) Water's polarity allows it to form covalent bonds with many substances 2) Natural water has a pH of approximately 5.6, which is slightly acidic. Acids can dissolve more substances than bases. 3) Because it is polar, water's oppositely charge ends are attracted to positively and negatively charged ions and molecules. Water molecules form a hydration shell around oppositely charged particles. 4) Because it is polar, water forms ionic bonds with the ions in substances such as NaCl (salt). 5) Because it is polar, water is able to interact with and dissolve hydrophobic substances.

3

Hydrophobic molecules are _____ water. 1) attracted to 2) absorbed by 3) repelled by 4) neutralized by 5) polarized by

3

In a group of water molecules, hydrogen bonds form between _____. 1) two hydrogen atoms in different water molecules 2) the oxygen atoms in different water molecules 3) the oxygen atom in one water molecule and a hydrogen atom in another water molecule 4) the hydrogen atoms in a single water molecule 5) none of the above

3

Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake? 1) 4.0 M 2) 10-10 M 3) 10-4 M 4) 104 M 5) 4%

3

Nonpolar molecules that cluster away from water molecules are called _____ molecules. 1) ionic 2) hydrophilic 3) hydrophobic 4) saponified 5) none of the above

3

Relative to other substances, water tends to resist changes in temperature. Why? 1) Water is extremely dense, and like all dense materials, it can absorb a great deal of heat with a relatively small change in temperature. 2) Water is abundant. Large bodies of water resist changes in their temperature simply because they are massive objects. 3) Water is highly cohesive. Its molecules tend to resist increases in their motion. When water is heated, some of the energy is used to disturb the hydrogen bonds between neighboring molecules. 4) Water is highly adhesive. Pure water does not resist temperature change, but if water is bonded to other substances, molecules will tend to "stay put" and resist increases in their motion.

3

Sweating has a cooling effect because of water's high _____. 1) Buffering capacity 2) surface tension 3) heat of vaporization 4) specific heat 5) density

3

The ability of water molecules to form hydrogen bonds with other water molecules and water's ability to dissolve substances that have charges or partial charges are _____. 1) both caused by water's ability to form covalent bonds with hydrophobic substances 2) due to water's partial charges and low molecular mass, respectively 3) both caused by water's partial charges 4) both caused by water's two electron shells and the opposite spins of those shells 5) both due to water's low molecular mass

3

The amount of heat required to convert 1 g of any substance from the liquid to the gaseous state is defined as _____. 1) the specific heat of that substance 2) 1 calorie 3) the heat of vaporization of that substance 4) the heat of fusion of that substance 5) molecular cohesion

3

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their 1) mass in daltons. 2) mass in grams. 3) number of molecules. 4) number of atoms. 5) volume.

3

What do cohesion, surface tension, and adhesion have in common with reference to water? 1) All are results of the structure of the hydrogen atom. 2) All are produced by covalent bonding. 3) All are properties related to hydrogen bonding. 4) All have to do with ionic interactions. 5) All are aspects of a crystalline structure.

3

What is the hydroxide ion concentration of the lake described in question 7? 1) 10-7 M 2) 10-4 M 3) 10-10 M 4) 10-14 M 5) 10 M

3

When the pH of a solution shifts from 7 to 3, how has the hydrogen ion concentration changed? 1) It has increased by 4 times. 2) It has decreased by 4 times. 3) It has increased by 10,000 times. 4) It has decreased by 10,000 times. 5) It has not changed.

3

Which of the following dissociations is that of an acid? 1) H2O → H+ + OH- 2) NaOH → Na+ + OH- 3) HF → H+ + F- 4) NH3 + H+ → NH4+ 5) KOH → K+ + OH-

3

Which of the following is a hydrophobic material? 1) paper 2) table salt 3) wax 4) sugar 5) pasta

3

Why is the increasing amount of carbon dioxide being taken up by the oceans a cause for concern? 1) The buffering action of carbonic acid (H2CO3) causes the pH of seawater to rise. 2) More carbon dioxide causes an increase in carbonic acid (H2CO3) which leads to an increase in the concentration of carbonate ion (CO32-). 3) More carbon dioxide causes an increase in carbonic acid (H2CO3) which leads to a decrease in the concentration of carbonate ion (CO32-). 4) There is no cause for concern. Carbonic acid (H2CO3) is an excellent buffer and will help keep the pH of seawater constant. 5) none of the above

3

A mole of ethyl alcohol weighs 46 g. How many grams of ethyl alcohol are needed to produce 1 L of a 2-millimolar (2 mM) solution? 1) 92 g 2) 9.2 g 3) 0.92 g 4) 0.092 g 5) 0.0092 g

4

Adhesion is best described as _____. 1) a property of water that helps moderate Earth's temperature 2) the process by which a crystalline lattice forms 3) the process that contributes to the transport of water and dissolved nutrients in plants by causing water molecules to tug on other water molecules 4) the clinging of one substance to another substance 5) none of the above

4

An acid is _____. 1) any compound with a pH 2) any compound that accepts hydrogen ions 3) a material that resists changes in the pH of a solution 4) a compound that donates hydrogen ions to a solution 5) a solution with a pH between 7 and 14

4

How many grams of acetic acid (C2H4O2) would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.) 1) 10.0 g 2) 0.1 g 3) 6.0 g 4) 60.0 g 5) 0.6 g

4

Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature? 1) water's change in density when it condenses 2) water's ability to dissolve molecules in the air 3) the release of heat by the formation of hydrogen bonds 4) the absorption of heat by the breaking of hydrogen bonds 5) water's high surface tension

4

The reason that coastal climates are more moderate than inland climates is due primarily to water's high _____. 1) heat of fusion 2) surface tension 3) heat of vaporization 4) specific heat 5) density

4

Water is sometimes called the "universal solvent." Is that accurate? 1) Certainly. Water's polar nature means that it can adhere to and dissolve all other substances. 2) Not at all. Only salts and carbohydrates can be dissolved in water. 3) For the most part. Water readily dissolves hydrophobic substances, but not hydrophilic ones. 4) For the most part. Water readily dissolves most substances, but not hydrophobic ones.

4

Which action would involve the greatest transfer of heat? 1) changing the temperature of 1 g of water from 10°C to 90°C 2) cooling 10 g of water from 80°C to 40°C 3) evaporating 1 g of water at 25°C 4) condensing 5 g of steam to liquid water 5) raising the temperature of 10 g of ethyl alcohol by 25°C

4

A glass of grapefruit juice, at pH 3, contains _____ H+ as a glass of tomato juice, at pH 4. 1) one-tenth as much 2) half as much 3) twice as much 4) three times as much 5) ten times as much

5

Cells are surrounded by water, and cells themselves consist of about 70% to 95% water. As a result _____. 1) the temperature of living things tends to change relatively slowly 2) a variety of nutrient molecules are readily available as dissolved solutes 3) waste products produced by cell metabolism can be easily removed 4) dissolved substances can be easily transported within a cell or between cells in multicellular organisms 5) all of the above

5

Sucrose has a molecular mass of 342 daltons. To make a 2-molar (2 M) solution of sucrose, _____. 1) stir 342 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution to 1 L 2) stir 684 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 2 L 3) stir 684 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 0.5 L 4) stir 342 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 2 L 5) stir 342 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 0.5 L

5

The tendency of water molecules to stay close to each other as a result of hydrogen bonding _____. 1) provides the surface tension that allows leaves to float on water 2) is called cohesion 3) keeps water moving through the vessels in a tree trunk 4) acts to moderate temperature 5) all of the above

5

How many molecules are contained in one mole? 6.02 X 10^23 6.02X10^22 6.02 X 10^21 6.02 X 10^24

6.02 X 10^23

The tendency of water molecules to stay close to each other as a result of hydrogen bonding does what?

?

Which of the following influence the physical state of water?

??

How many molecules are contained in one mole?

A) 6.02 X 10^23

___________ is an example of a hydrophobic molecule, whereas ___________ is an example of a hydrophilic molecule.

A) Fat, sugar

Why does water have so many of the unique characteristics that it does?

A) Hydrogen Bonds allow it to interact with itself and other polar molecules.

Why does NaCl dissociate in water and not glucose?

A) NaCl is bound by ionic bonds and glucose atoms are covalently bonded.

Tom is in his chemistry class and notices that the water in his test tube forms a "U" shape (meniscus) on the top surface. What reasonable conclusion can be made based on this information?

A) The test tube is made of polar molecules.

Water is a good solvent for __________ molecules, because it has __________ with the solutes.

A) hydrophilic, electrical charge attractions ??

Substances dissolved in water are called _________.

A) solutes.

The ability of water to stick to other polar substances is termed:

Adhesion

What do cohesion, surface tension, and adhesion have in common with reference to water? (eText Concept 3.2)

All are properties related to hydrogen bonding.

To make a 1% solution of glucose, you would dissolve ____ gram(s) of glucose into enough water to make a 100mL solution.

B) 1

When one mole of potassium chloride (KCl) dissolves in water it dissociates into two ions. After the ions dissociate we could say that there is/are __________ mole(s) of K+ in solution and __________ mole(s) of Cl- in solution.

B) 1, 1

If you place 2 Osm of NaCl into water, what is the osmolarity of Na+ in water?

B) 1.0 Osm

How does the polarity of water contribute to its ability to dissolve so many substances?

Because it is polar, water's oppositely charged ends are attracted to positively and negatively charged ions and molecules. Water molecules form a hydration shell around oppositely charged particles.

How does the polarity of water contribute to its ability to dissolve so many substances? (eText Concept 3.2)

Because it is polar, water's oppositely charged ends are attracted to positively and negatively charged ions and molecules. Water molecules form a hydration shell around oppositely charged particles.

Which of the following statements about water is true? 1. Water participates in Hydrogen bonding. 2. Water is an important element in our bodies. 3. Hydrogen and oxygen in water are held together by an ionic bond. 4. Electrons are shared equally between the hydrogen and oxygen.

C) 1, 2 ?

Which statement is NOT true about water?

C) Water is a nonpolar solvent

In order to produce a 9% solution of glucose, I should add 9 __________ of glucose to 100 __________ of water.

C) grams, milliliters

Osmolarity differs from molarity

C) osmolarity reflects the number of particles in solution

Electrolytes are

D) cations and anions that dissociate in water. -

Ions dissolved in water could be called ________.

D) electrolytes

One calorie is the amount of energy needed to raise the temperature of one __________ of water one degree __________.

D) gram, Celsius

Which of the following statements about water is true?

E) all of the above

You are given two unknown liquids labeled X and Y. You decide to run some experiments to determine what they are. You pour the liquids into separate beakers and begin to heat them up. As the liquids sit on the hot plate you notice that liquid X heats up much faster and begins to boil. Based on this information, what can you conclude about the hydrogen bonds in each liquid?

F) b and d

How does water help to maintain the body's temperature even when the weather is cold?

H) a and d

Important electrolyte(s) in the body include...

H) all of the above

Which of the following dissociations is that of an acid?

HF --> H+ + F-

Which of the following dissociations is that of an acid? (eText Concept 3.3)

HF → H+ + F

Which of the following dissociations is that of an acid?

HF → H+ + F-

Why does water have so many of the unique characteristics that it does? Hydrogen Bonds allow it to interact with itself and other polar molecules. Its covalent bonds are easily broken so H and O can interact with other molecules. Having 2 Hydrogen's in one molecule allow it to be extremely reactive. It is able to interact with molecules that are both polar and nonpolar.

Hydrogen Bonds allow it to interact with itself and other polar molecules.

what are the four most abundant elements in living systems?

Hydrogen, oxygen, nitrogen and carbon CHON

Ionic compounds tend to be...

Hydrophilic and disassociate in water readily.

What water-related evidence do scientists have that suggests life may exist on other planets? (eText Concept 3.2)

In 2008, the robotic spacecraft Phoenix found ice present just under the material on Mars's surface, and detected sufficient water vapor in the Martian atmosphere for frost to form.

Why are cell membranes composed primarily of hydrophobic molecules

In order to perform their function of separating the aqueous solutions outside of cells from the aqueous solutions inside of cells, cell membranes cannot be soluble in water.

Why are cell membranes composed primarily of hydrophobic molecules? (eText Concept 3.2)

In order to perform their function of separating the aqueous solutions outside of cells from the aqueous solutions inside of cells, cell membranes cannot be soluble in water.

When pH shifts from 7 to 3, how has the hydrogen ion concentration changed?

It has increased by 10,000 times.

When the pH of a solution shifts from 7 to 3, how has the hydrogen ion concentration changed?

It has increased by 10,000 times.

Which of the following statements is true about acid precipitation

It has the most pronounced effect on lakes and streams in the early spring.

What is the difference between molarity and osmolarity? Molarity refers to moles per liter and osmolarity refers to grams per 100 ml Molarity is used for solutes added to water and osmolarity considers any dissociation that may occur in water. Molarity is more accurate to use when referring to solute concentration in body fluids All of the above are TRUE statements

Molarity is used for solutes added to water and osmolarity considers any dissociation that may occur in water.

Why is the increasing amount of carbon dioxide being taken up by the oceans a cause for concern? ()

More carbon dioxide causes an increase in carbonic acid (H2CO3), which leads to a decrease in the concentration of carbonate ion (CO32-).

Why is the increasing amount of carbon dioxide being taken up by the oceans a cause for concern? (eText Concept 3.3)

More carbon dioxide causes an increase in carbonic acid (H2CO3), which leads to a decrease in the concentration of carbonate ion (CO32-).

Why does NaCl dissociate in water and not glucose? NaCl is bound by ionic bonds and glucose atoms are covalently bonded. Glucose is bound by ionic bonds and NaCl atoms are covalently bonded. Glucose is a much larger molecule so it can't be broken down by water. Glucose is hydrophobic.

NaCl is bound by ionic bonds and glucose atoms are covalently bonded

If water were not a polar molecule, how would the effects of global warming differ from what are currently observed or predicted to occur in the future?

The effects would be drastically worse because the loss of the polar nature of water would greatly reduce its specific heat and its ability to moderate temperature.

If water were not a polar molecule, how would the effects of global warming differ from what are currently observed or predicted to occur in the future? (eText Concept 3.2)

The effects would be drastically worse because the loss of the polar nature of water would greatly reduce its specific heat and its ability to moderate temperature.

Which of the following accurately relates the emergent properties of water to the effects of global warming in the Arctic? (eText Concept 3.2)

The significant increase in Arctic air temperature over the past 50 years is causing sea ice to form later in the year, to melt earlier, and to cover a smaller area each year.

Consider the previous question again. If 3 moles of MgCl2 are put in a Liter of water then which of the following statements is TRUE? (Mark all that are TRUE...there may be more than one). The solution would have a molarity of 1 The solution would have a molarity of 3 The solution would have an osmolarity of 3 The solution would have an osmolarity of 6 The solution would have a molarity of 6 The solution would have a molarity of 1.5 The solution would have an osmolarity of 1.5 The solution would have an osmolarity of 9

The solution would have an osmolarity of 9 The solution would have a molarity of 3

Tom is in his chemistry class and notices that the water in his test tube forms a "U" shape (meniscus) on the top surface. What reasonable conclusion can be made based on this information? The test tube is made of polar molecules. Atmospheric pressure is pushing down more on the center than on the sides. Test tubes are rounded at the bottom so the center of the water column will be lower than the sides. The test tube needs more water to make it level.

The test tube is made of polar molecules

What is the role of van der Waals interactions in biological molecules?

Weak bonds are important in the three-dimensional structure of most large biological molecules, and they play a role in molecular interactions.

Which of the following influence the physical state of water? number of intermolecular bonds temperature size of the water molecules a and b a and c all of the above

a and b

An acid is _____.

a compound that donates hydrogen ions to a solution

An acid is _____. (eText Concept 3.3)

a compound that donates hydrogen ions to a solution

Water molecules have _____ than molecules of similar size, such as ammonia and methane, reflecting its capacity to absorb large amounts of heat. (eText Concept 3.2)

a higher boiling point

The osmolarity of a solution is _________. a measure of solute concentration. a measure of solute type. the weight of a solid substance. reflects a measure of the amount of oil dissolved in a water. a scientific term for determining the solubility of a substance in water.

a measure of solute concentration

what type of bond is a hydrogen bond?

a weak chemical bond

You are given two unknown liquids labeled X and Y. You decide to run some experiments to determine what they are. You pour the liquids into separate beakers and begin to heat them up. As the liquids sit on the hot plate you notice that liquid X heats up much faster and begins to boil. Based on this information, what can you conclude about the hydrogen bonds in each liquid? Liquid X can form more hydrogen bonds. Liquid Y can form more hydrogen bonds. Liquid X has a higher heat of vaporization. Liquid Y has a higher heat of vaporization. a and d b and d a and c b and c

b and d

Electrolytes are nonpolar molecules. substances that usually don't dissolve in water. found in solutions that do not conduct electricity. cations and anions that dissociate in water.

cations and anions that dissociate in water

The phenomenon responsible for maintaining the upward movement of water through a vessel is _____. (eText Concept 3.2)

cohesion

When ionic compounds are placed in water, their ions ________.

dissociate or separate from one another.

Cells are surrounded by water, and cells themselves consist of about 70 to 95% water. As a result, _____. (eText Concept 3.1)

dissolved substances can be easily transported within a cell or between cells in multicellular organisms ,the temperature of living things tends to change relatively slowly ,waste products produced by cell metabolism can be easily removed ,a variety of nutrient molecules is readily available as dissolved solutes ,All of the listed responses are correct.

Ions disassociated in water could be called ________.

electrolytes

which of the following has negligible mass?

electron

what does the number of protons in an uncharged atom equal?

equals the number of electrons

___________ is an example of a hydrophobic molecule, whereas ___________ is an example of a hydrophilic molecule. Fat, sugar Oil, fat salt, oil salt, sugar

fat, sugar

Pure water has a pH of 7. Why does uncontaminated rainwater have a pH of 5.6? (eText Concept 3.3)

formation of carbonic acid from carbon dioxide and water

In order to produce a 9% solution of glucose, I should add 9 __________ of glucose to 100 __________ of water. milligrams, milliliters milligrams, deciliters grams, milliliters grams, liters

grams, milliliters

a polar covalent bond is a bond that what?

has shared electrons pulled closer to the more electronegative atom

Hydrophilic substances, but not hydrophobic substances, _____.

have charges and partial charges to which water molecules can adhere

Sweating has a cooling effect because of water's high _____. (eText Concept 3.2)

heat of vaporization

Water resists temperature change because _____.

heating water absorbs energy by disrupting the hydrogen bonds before evaporation can occur Hydrogen bonding makes water molecules more cohesive.

Ionic compounds tend to be... Hydrophobic and dissolve in water readily Hydrophobic and don't dissolve in water Hydrophilic and don't dissolve in water Hydrophilic and dissolve in water readily.

hydrophilic and dissolve in water readily

A molecule that has all nonpolar covalent bonds would be _____.

hydrophobic

A molecule that has all nonpolar covalent bonds would be _____. (eText Concept 3.2)

hydrophobic

Nonpolar molecules that cluster away from water molecules are called _____ molecules

hydrophobic

Nonpolar molecules that cluster away from water molecules are called _____ molecules. (eText Concept 3.2)

hydrophobic

A molecule that has all nonpolar covalent bonds would be _____.

hydrophobic Hydrophilic substances are polar.

Because molecules of water are farther apart in ice than in liquid water, _____. (eText Concept 3.2)

ice floats

Because the molecules of water are farther apart in ice than in liquid water, _____.

ice floats

Because molecules of water are farther apart in ice than in liquid water, _____.

ice floats Because water molecules in ice are farther apart than in liquid water, ice is less dense, and therefore, it floats.

water is a polar molecule, which means what?

in the case of water, the oxygen is slightly negative and the hydrogen atoms are slightly positive

Adding acid tends to _____ of a solution.

increase the hydrogen ion concentration and lower the pH

Adding acid tends to _____ of a solution. (eText Concept 3.3)

increase the hydrogen ion concentration and lower the pH

Adding acid tends to ____ of a solution.

increase the hydrogen ion concentration and lower the pH As the hydrogen ion concentration increases, the pH declines.

The absorption of human-generated CO2 by the oceans _____. (eText Concept 3.3)

increases the hydrogen ion concentration in the oceans but decreases the carbonate ion concentration and threatens the livability of the oceans for calcifying organisms

A milliosmole is 1/10 of an osmole is 1/100 of an osmole is 1/1000 of an osmole is 1/10,000 of an osmole

is 1/1000 of an osmole

When the pH of a solution shifts from 7 to 3, how has the hydrogen ion concentration changed? (eText Concept 3.3)

it has increased by 10,000 times.

Adding a base tends to _____ of a solution.

lower hydrogen ion concentration and increase the pH A lower pH means a higher hydrogen ion concentration.

Adding a base tends to _____ of a solution

lower the hydrogen ion concentration and increase the pH

Adding a base tends to _____ of a solution. (eText Concept 3.3)

lower the hydrogen ion concentration and increase the pH

a covalent bond is likely to be polar if what?

one of the atoms sharing electrons is much more electronegative

Most of water's unique features (for example, its versatility as a solvent, ability to moderate temperature, and cohesive behavior) result from the fact that _____.

oxygen attracts electrons more than hydrogen does

Most of water's unique features (for example, its versatility as a solvent, ability to moderate temperature, and cohesive behavior) result from the fact that _____. (eText Concept 3.2)

oxygen attracts electrons more than hydrogen does

The most widely effective solvent is a material that is _____.

polar

Water is a very versatile solvent because water molecules are _____. (eText Concept 3.2)

polar

Water is a very versatile solvent because water molecules are _____.

polar Because molecules of polar solvents have a positive and a negative pole, polar solvents are excellent solvents for ions and for other polar materials. --------------------------------------------------------------------------------

The tendency of water molecules to stay close to each other as a result of hydrogen bonding _____. (eText Concept 3.2)

provides the surface tension that allows leaves to float on water , acts to moderate temperature , keeps water moving through the vessels in a tree trunk , is called cohesion

What is NOT a biological function of water? protection and lubrication regulation of blood volume involved in many chemical reactions necessary for life stabilizing body temperature

regulation of blood volume

Hydrophobic molecules are _____ water. (eText Concept 3.2)

repelled by

Substances dissolved in water are called _________.

solutes

Substances dissolved in water are called _________. solutes. solvents. catalysts. osmoles. insoluble.

solutes

The reason that coastal climates are more moderate than inland climates is due primarily to water's high _____. (eText Concept 3.2)

specific heat

Sucrose has a molecular mass of 342 daltons. To make a 2-molar (2 M) solution of sucrose, _____. (eText Concept 3.2)

stir 342 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 0.5 L

Sucrose has a molecular weight of 342 daltons. To make a 2-molar (2 M) solution of sucrose, _____.

stir 342 grams of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 0.5

You can fill a glass of water to just slightly above the rim without it spilling over the glass. What property of water best explains this phenomenon? (eText Concept 3.2)

surface tension

A glass of grapefruit juice, at pH 3, contains _____ H+ as a glass of tomato juice, at pH 4

ten times as much

A glass of grapefruit juice, at pH 3, contains _____ H+ as a glass of tomato juice, at pH 4. (eText Concept 3.3)

ten times as much

Adhesion is best described as _____.

the clinging of one substance to another substance

Adhesion is best described as _____. (eText Concept 3.2)

the clinging of one substance to another substance

The amount of heat required to convert 1 g of any substance from the liquid to the gaseous state is defined as _____. (eText Concept 3.2)

the heat of vaporization of that substance

the chemical characteristics or reactivity of an element depend mostly on what?

the number of electrons in the outer most shell

Water is a polar molecule. This means that _____. (eText Concept 3.1)

the opposite ends of the molecule have opposite electrical charges

In a group of water molecules, hydrogen bonds form between _____.

the oxygen atom in one molecule and a hydrogen atom in another molecule

In a group of water molecules, hydrogen bonds form between _____. (eText Concept 3.1)

the oxygen atom in one water molecule and a hydrogen atom in another water molecule

In a group of water molecules, hydrogen bonds form between what?

the oxygen atom in one water molecule and a hydrogen atom in another water molecule

The amount of heat required to change the temperature of 1 g of any substance by one °C is defined as _____. (eText Concept 3.2)

the specific heat of that substance

The partial charges on a water molecule occur because of _____.

the unequal sharing of electrons between hydrogen and oxygen Consider the nature of the type of covalent bonds found within a water molecule.

the partial charges on a water molecule occur because of what?

the unequal sharing of electrons between the hydrogen and oxygen atoms Because oxygen is more electronegative than hydrogen, electrons of the polar bond spend more time closer to the oxygen atom, resulting in a slight negative charge on the oxygen atom and slight positive charges on the hydrogen atoms.

The partial charges on a water molecule occur because of _____. (eText Concept 3.1)

the unequal sharing of electrons between the hydrogen and the oxygen atoms of a water molecule

Which of the following statements is true about chemical reactions? (

they involve the making and breaking of chemical bonds

Which statement is NOT true about water? Pure water is a non-electrolyte The attraction of water molecules to each other is called cohesion Water is a nonpolar solvent Approximately 92% of plasma is water

water is a non polar solvent

Hydrogen bonds cause surface tension in water, allowing some small organisms, like water striders, to move around on the surface of the water without getting wet. If you introduce soap (a large compound made up of polar covalent bonds) to the water, the surface tension disappears, and the water striders will sink into the water. This is because... Water striders can't swim Water makes hydrogen bonds with the soap instead of with itself, disrupting the surface tension Soap dissociates in the water, becoming an electrolyte, and disrupting the surface tension Soap creates new covalent bonds with water, becoming non-polar so surface tension disappears None of the above.

water makes hydrogen bonds with the soap instead of with itself, disrupting the surface tension

The attraction of unlike substances is termed _____.

adhesion

Important electrolyte(s) in the body include... K+ Na+ Ca2+ Cl- HC03- H+ Mg2+ all of the above only a through f

all of the above

Why is it important to drink adequate amounts of water each day? Water helps to regulate body temperature. Water helps to lubricate the joints. Water dissolves solutes, which allows chemical reactions to occur. all of the above

all of the above

when the proton number and electron number are unequal, the atom or molecules is what?

an ion

In water, hydrogen bonding occurs between the hydrogen atom in one molecule and __________. an oxygen atom in the same molecule an oxygen atom in a different molecule a hydrogen atom in the same molecule a hydrogen atom in a different molecule

an oxygen atom in a different molecule

Sodium chloride (NaCl) dissolves in water because water molecules _____.

are polar

isotopes of an element will always differ in what?

atomic mass

ionic bonds are formed as a result of what?

attraction between ions that have opposite charges

What is the difference between molarity and osmolarity?

B) Molarity is used for solutes added to water and osmolarity considers any dissociation that may occur in water.

Consider the previous question again. If 3 moles of MgCl2 are put in a Liter of water then which of the following statements is TRUE? (Mark all that are TRUE...there may be more than one).

B) The solution would have a molarity of 3 H) The solution would have an osmolarity of 9 -

Hydrogen bonds cause surface tension in water, allowing some small organisms, like water striders, to move around on the surface of the water without getting wet. If you introduce soap (a large compound made up of polar covalent bonds) to the water, the surface tension disappears, and the water striders will sink into the water. This is because...

B) Water makes hydrogen bonds with the soap instead of with itself, disrupting the surface tension

In water, hydrogen bonding occurs between the hydrogen atom in one molecule and __________.

B) an oxygen atom in a different molecule

When ionic compounds dissolve in water, their ions ________.

B) dissociate or separate from one another.

What is NOT a biological function of water?

B) regulation of blood volume

The ability of water molecules to form hydrogen bonds with other water molecules and water's ability to dissolve substances that have charges or partial charges are _____.

both caused by water's partial charges

The ability of water molecules to form hydrogen bonds with other water molecules and water's ability to dissolve substances that have charges or partial charges are _____. (eText Concept 3.2)

both caused by water's partial charges

Water molecules are known for forming hydrogen bonds between themselves and for their ability to dissolve a great variety of substances that have charges or partial charges on their molecules. These two properties are ___________.

both caused by water's partial charges

A substance that minimizes changes in the concentration of H+ and OH- in a solution is a _____.

buffer

A substance that minimizes changes in the concentration of H+ and OH-in a solution is a _____. (eText Concept 3.3)

buffer