ch 3
How many molecules of glycerol (C3H8O3) would be present in 1L of a 1M glycerol solution?
a) 14 b) 92 c) 1x10/7 d) 1 e) 6.02 x 10/23
Water is able to form hydrogen bonds because:?
a) oxygen has a valence of 2 b) the oxygen atom in a water molecule has a weak positive charge c) the bonds that hold together the atoms in a water molecule are polar covalent bonds d) each of the hydrogen atoms in a water molecule is weakly negative in charge e) the water molecule is shaped like a tetrahedron
What gives rise to the cohesiveness of water molecules?
a) nonpolar covalent bonds b) hydrophobic interactions c) ionic bonds d) hydrogen bonds e) both A and C
What is the pH of a solution with a hydrogen ion [H+] concentration of 10/-8 M?
a) pH 2 b) pH 10 c) pH 8 d) pH 4 e) pH 6
One of the buffers that contribute to pH stability in human blood is carbonic acid H2CO3. Carbonic acid is a weak acid that when placed in an aqueous solution dissociates into a bicarbonate ion (HCO3_) and a hydrogen ion (H+) Thus, H2CO3>HCO3-H+ If the pH of the blood increases, one would expect:
a decrease in the concentration of H2CO3 and an increase in the concentration of H2O
The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20kg of water how many degrees Celsius?
a) 0.2c b) 20.0c c) 10.0c d) 1.0c e) 2.0c
One liter of a solution pH9 has how many more hydroxyl ions (OH-) than 1L of a solution of pH 4?
a) 1,000 times b) 10,000 times c) 100,000 times d) 100 times more e) 5 times more
Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake?
a) 10/-10 M b) 10/-4 M c) 4.0 M d) 10/4 M e) 4%
Equal volumes of vinegar from a freshly-opened bottle are added to each of the following solutions. After complete mixing, which of the mixtures will have the highest pH?
a) 100mL of freshly-squeezed orange juice b) 100mL of household cleanser containing 0.5M ammonia c) 100mL of freshly brewed coffee d) 100 mL of pure water e) 100mL of tomato juice
When an ionic compound such as sodium chloride (NaCl) is placed in water the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast the atoms of covalently bonded molecules do no generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of particles (molecules or ions)?
a) 1L of 0.5M NaCl b) 1L of 0.5M glucose c) 1L of 1.0M glucose d) 1L of 1.0M NaCl e) C and D will contain equal numbers of particles
A slice of pizza has 500kcal. 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? ( a liter of cold water weighs about kg)
a) 1c b) 5c c) 10c d) 100c e) 50c
You have a freshly-prepared 1M solution of glucose water. You carefully pour out a 100mL sample of the solution. How many glucose molecules are included in that 100mL sample?
a) 3.01 x 10/23 b) 12.04 x 10/23 c)6.02 x 10/23 d) 6.02x 10/24 e) 6.02 x 10/22
You have a freshly-prepared 0.1M solution of glucose in water. Each liter of this solution contains how many glucose molecules?
a) 3.01 x 10/23 b) 6.02 x 10/21 c) 12.04 x 10/23 d) 6.02 x 10/22 e) 6.02 x 10/23
One liter of a solution of pH 2 has how many more hydrogen ions (H+) than 1.1 of a solution of pH 6?
a) 4 times more b) 10,000 times more c) 4,000 times more d) 400 times more e) 100,000 times more
Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion concentration of this lake?
a) 4.0M with regard to hydroxyl ion concentration b) 1 x 10/-10 mol of hydroxyl ion per liter of lake water c) 1x10/-4 mol of hydroxl ion per liter of lake water d) 10.0M with regard to hydroxly ion concentration e) both B and D
At what temperature is water at its densest?
a) 4c b) 100c c) 212c d) 32c e) 0c
You have two beakers. One contains a solution of HC1 at pH=1.0. The other contains a solution of NaOH at pH=13. Into a third beaker, you slowly and cautiously pour 20mL of the HCL and 20 mL of the NaOH. After complete stirring, the pH of the mixture will be:
a) 5.0 b) 12.0 c) 2.0 d) 7.0 e) 9.0
The molecular weight of water is 18 daltons. What is the molarity of 1 L of pure water?
a) 55.6 M b) 0.66 M c) 18M d) 1.0M e) 37M
How many molecules of glucose (C6H2O6 molecular mass =180 daltons)would be present in one mole of glucose?
a) 6.02 x 10/23 b) 342 c) 180 x 10/14 d) 24 e) 23 x 10/14
One mole (mol) of a substance is:
a) 6.02 x 10/23 molecules of the substance b) the largest amount of the substance that can be dissolved in 1L of solution c) 1g of the substance dissolved in 1L of solution d) the molecular mass of the substance expressed in grams e) A and D only
How many grams of acetic acid (C2H4O2) would you use to make 10L of a 0.1M aqueous solution of acetic acid? (the atomic masses, in daltons, are apporximately 12 for carbon, 1 for hydrogen, and 16 for oxygen)
a) 60.0g b) 10.0g c) 0.6g d) 0.1g e) 6.0g
Which of the following ionizes completely in solution and is considered to be a strong base (alkali)?
a) NH3 b) NaOH c) HCl d) NaCl e) H2CO3
Which of the following statements is completely correct?
a) NH3 is a weak base (alkali), and HCl is a strong acid b) NH3 is a strong base (alkali), and HCl is a weak acid c) H2CO3 is a strong acid, and NaOH is a strong base (alkali) d) H2CO3 is a weak acid, and NaOH is a weak base (alkali) e) NH3 is a weak base (alkali) and H2CO3 is a strong acid
You have two beakers; one contains pure water, the other contains pure methanol ( wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt into each beaker. Predict what will happen:
a) NaCl crystals will NOT dissolve in either water or methanol b) when the first crystals of NaCl are added to water or to methanol, they will not dissolve; but as more crystals are added, the crystals will begin to dissolve faster and faster c) NaCl crystals will dissolve readily in methanol but will not dissolve is water d) NaCl crystal will dissolve readily in water but will not dissolve in methanol e) equal amounts of NaCl crystals will dissolve in both water and methanol
Which of the following ionizes completely in solution and is considered to be a strong acid?
a) NaOH b) HCl c) H2CO3 d) CH3COOH e) NH3
A solution contains 0.00000001 (10/-7) moles of hydroxyl ions [OH-] per liter. Which of the following best describes this solution?
a) basic: H+ acceptor b neutral c) basic: H+ donor d) acidic: H+ donor e) acidic H+ acceptor
A given solution contains 0.0001 (10/-4) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution?
a) basic: H+ donor b) acidic H+ acceptor c) neutral d) basic: h+ acceptor e) acidic: H+ donor
Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2+H2O>H2CO3. Carbonic acid (H2CO3) is a weak acid. Respiring cells release CO2. What prediction can we make about the pH of blood as that blood first comes in contact with respiring cells?
a) blood pH will increase slightly b) blood pH will first decrease, then increase sharply as CO2 combines with hemoglobin c) blood pH will decrease slightly d) blood pH will remain unchanged e) blood pH will first increase, then decrease as CO2 combines with hemoglobin
If the pH of a solution is decreased from 9 to 8, it means that the:?
a) concentration of H+ has decreased to one-tenth (1/10) what it was at pH 9 b) concentration of H+ has increased 10-fold (10x) compared to what it was at pH9 c) concentration of OH- has increased 10-fold (10x) compared to what it was at pH9 d) concentration of OH- has decreased to one-tenth (1/10) what it was at pH9 e) both B and D are correct
If the pH of a solution is increased from pH 5 to pH 7, it means that the:?
a) concentration of H+ is twice (2x) what is was at pH 5 b) concentration of H+ is 100 times greater and the concentration of OH- is one-hundredth what they were at pH 5 c) concentration of OH- is 100 times greater than what it was pH 5 d) concentration on OH- is one-hundredth (0.01X) what it was at pH 5 e) concentration of H+ is half (1/2) what it was at pH5
Research indicates that acid precipitation can damage living organisms by:?
a) decreasing the H+ concentration of lakes and streams b) increasing the OH- concentration of lakes and streams c) washing away the certain mineral ions that help buffer soil solution and are essential nutrients for plant growth d) buffering aquatic systems such as lakes and streams e) both B and C
The molecular mass of glucose (C6H12O6) is 180g. Which of the following procedures should you carry out to make a 0.5M solution of glucose?
a) dissolve 0.5g of glucose in 1L of water b) dissolve 180g of glucose in 1L of water c) dissolve 0.5g of glucose in a small volume of water, and then add more water until the total volume of solution is 1L d) dissolve 180g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1L e) dissolve 90g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1L
The molecular mass of glucose is 180g. Which of the following procedures should you carry out to make a 1M solution of glucose?
a) dissolve 180 g of glucose in 1L of water b) dissolve 1g of glucose in 1L of water c) dissolve 180g of glucose in 100g of water d) dissolve 180g of glucose in water, and then add more water until the total volume of the solution is 1L e) dissolve 180mg of glucose in 1L of water
Which of the following takes place as an ice cube cools a drink?
a) evaporation of the water in the drink increases b) molecular collisions in the drink increase c) a calorie of heat energy is transferred from the ice to the water of the drink d) the specific heat of the water in the drink decreases e) kinetic energy in the drink decreases
Which of the following solutions has the greatest concentration of hydrogen ions [H+]?
a) gastric juice at pH 2 b) tomato juice at pH 4 c) household bleach at pH 12 d) vinegar at pH 3 e) black coffee pH 5
Waters high specific heat is mainly a consequence of the?
a) high specific heat of oxygen and hydrogen atoms b) fact that water is a poor heat conductor c) small size of the water molecules d) inability of water to dissipate heat into dry air e) absorption and release of heat when hydrogen bonds break and form
The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
a) hydrophilic bond b) covalent bond c) ionic bond d) hydrogen bond e) hydrophobic bond
Which type of bond must be broken for water to vaporize?
a) ionic bonds b) covalent bonds c) hydrogen bonds d) nonpolar convalent bonds e) polar convalent bonds
We can be sure that a mole of table sugar and a mole of vitamin C are equal in their?
a) mass in grams b) number of atoms c) volume d) mass in daltons e) number of molecules
Which of the following effects is produced by the high surface tension of water?
a) organisms resist temperature changes, although they give off heat due to chemical reactions b) lakes don't freeze solid in winter, despite low temperatures c)the pH of water remains exactly neutral d) a water strider can walk across the surface of a small pond e) water can act as a solvent
What is the pH of a solution with a hydroxyl ion [OH-} concentration of 10/-12 M?
a) pH 4 b) pH 10 c) pH 12 d) pH 14 e) pH 2
Which of the following is a hydrophobic material?
a) pasta b) wax c) sugar d) table salt e)paper
The bonds that are broken when water vaporizes are:
a) polar covalent bonds b) ionic bonds c) nonpolar covalent bonds d) hydrogen bonds between water molecules e) covalent bonds between atoms within water molecules
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by:
a) polar covalent bonds b) ionic bonds c) van der Waals interactions d) nonpolar covalent bonds e) hydrogen bonds
Hydrophobic substances such as vegetable oil are:?
a) polar substances that repel water molecules b) nonpolar substances that have an attraction for water molecules c) nonpolar substances that repel water molecules d) charged molecules that hydrogen-bond with water molecules e) polar substances that have an affinity for water
Buffers are substances that help resist shifts in pH by:?
a) releasing OH- in basic solutions b) donating H+ to a solution when they have been depleted c) releasing H+ in acidic solutions d) accepting H+ when they are in excess e) both B and D are correct
Many minerals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?
a) the absorption of heat by the breaking of hydrogen bonds b) water's high surface tension c) water's change in density d) water's ability to dissolve molecules in the air e) the release of heat by the formation of hydrogen bonds
Which of the following statements correctly defines a kilocalorie?
a) the amount of heat required to raise the temperature of 1,000g of water by 1F b) they amount of heat required to raise the temperature of 1g of water by 1F c) the amount of heat required to raise the temperature of 1kg of water by 1c d) the amount of heat required to raise the temperature of 1kg of water by 1F e) the amount of heat required to raise the temperature of 1g of water by 1C
A 100mL beaker contains 10 mL of NaOH solution at pH=13. A technician carefully pours into the beaker, 10 mL of HCl at pH =1. Which of the following statements correctly describes the results of this mixing?
a) the concentration of Cl- ion falls b) the concentration of undissociated H2O molecules remains unchanged c) the pH of the beakers contents fails d) the pH of the beakers contents rises e) the concentration of Na+ ion rises
If the pH of the blood drops, one would expect:
a) the concentration of bicarbonate ion (HCO3-) to increase b) the HCO3- to act as a base and remove excess H+ with the formation of H2CO3 c) the concentration of hydroxide ion (OH-) to increase d) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3_ e) the HCO3- to act as an acid and remove excess H+ with the formation of H2CO3
Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that:
a) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y b) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen ions in solution Y c) solution Y has no free hydrogen ions (H+) d) the concentration of hydrogen ions in solution Y is 1,000 times as great as the concentration of hydrogen ions in solution X e) none of the other answer choices correctly describes these solutions
Why does ice float in liquid water?
a) the crystalline lattice of ice causes it to be denser than liquid b) ice always has air bubbles that keep it afloat c) the ionic bonds between the molecules in ice prevent the ice from sinking d) hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water e) the liquid water molecules have more kinetic energy and thus support the ice
Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?
a) the release of heat by the breaking of hydrogen bonds b) the change in density when it condenses to form a liquid or solid c) the high surfaces tension of water d) reactions with other atmospheric compounds e) the release of heat by the formation of hydrogen bonds
An example of hydrogen bond is the bond between:
a) the two hydrogen atoms in a molecule of hydrogen gas (H2) b) the H of one water molecule and the O of another water molecule c) Mg+ and Cl- in MgCl2 d) C and H in methane (CH4) e) Na+ and Cl- in salt
Pure, freshly-distilled water has a pH of 7. This means that:
a) there are no OH- ions in the water b) the concentration of H+ ions in the water equals the concentrations of OH- ions in the water. c) the concentration of OH- ions in the water is 7 times the concentration of OH- ions in the water d) the concentration of H+ ions in the water is 7 times the concentration of OH- ions in the water e) there are no H+ ions in the water
Which of the following statements is TRUE about buffer solutions?
a) they maintain a relatively constant pH when either acids or bases are added to them b) they maintain a constant pH when bases are added to them but not when acids are added to them c) they are found only in living systems and biological fluids d) they maintain a constant pH when acids are added to them but now when bases are added to them e) they maintain a constant pH of exactly 7 in all living cells and biological fluids
Which of the following solutions has the greatest concentration of hydroxyl ions [OH-}?
a) tomato juice at pH 4 b) urine at pH 6 c) vinegar at pH 3 d) seawater at pH 8 e) lemon juice pH 2
Based on your knowledge of the polarity of water molecules, the solute molecule is most likely:
a) without charge b) nonpolar c) negatively charged d) positively charged e) hydrophobic