TB Chapter 2

Seven steps listed, Which four do you need to prepare solution SKIP

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A hydronium ion has structure H3O+ Is a hydrated hydrogen ion Is a hydrated protein Is the usual form of one of the dissociate products of water All of the above

all of the above

Osmosis is the movement of

water molecules across a membrane

According to the titration curve to the right, acid A is _______ because the ph ________

weak, resists change

According to the Henderson-Hasselbalch equation, when does pH= to pKa

when concentration of conjugate base is equal to concentration of the acid

Buffers true statement

when pH=pKa, the weak acid and salt concentrations in a buffer are equal

Which factor contributes to the bent shape of water molecule?

Unshared electron pairs on Oxygen atom

Which compound acts as a diprotic acid? CH3COOH NH4 H2CO3 H3PO4 CH3CH2OH

H2CO3

The conjugate base of H2PO4 is

HPO4(2-)

List acids in increasing order of strength Nitrous Acid, Carbonic Acid, Acetic Acid, Phosphoric Acid

Carbonic, Acetic, Nitrous, Phosphoric

Which statement correctly describes situation of cell in diagram? Black dots= solute molecules

Cell is in hypertonic solution, water will move out and cause cell to shrink

The aqueous solution with the LOWEST pH is .1M HCL .1M acetic acid .1M formic Acid .1M HCL 10^12M NaOH

0.1M HCl

Which attributes contribute to waters unusual properties?

Geometry, Polarity, Hydrogen Bonds, Dipole Moment

The aqueous solution with the highest ph is 1M HCl 1M NH3 .5M NaHCO3 .1M M NaOH .001 M NaOH

.1M NaOH

pH of solution of 1M HCL is

0

milk of magnesia has a pH of 10.2. What is the OH

1.58*10^4

A 0.6M solution of a weak acid had a pH of 5.8, What is the pKa of solution

11.3

pH of solution of 0.1M NaOH is

13

Formic acid is used in venom. What is the pH of .2M solution of formic acid. Ka= 1.78*10^4?

2.2 Ionization of water

According to curve, acid A has buffering range of

2.8-4.8

According to titration curve to the right, acid A has a pKa of

3.8

Distilled White Vinegar has pH of 2.4 water as reactant. What is H of distilled white vinegar?

3.98*10^3

The H concentration of solution is 5.6*10^5M. What is pH

4.25

The OH concentration of solution is 4.3 *10^10 M. What is the pH?

4.63

A 1.0M solution of compound with 2 ionizable groups has a pH of 6.8. If biochemist adds 60mL of 1M HCl to solution. The solution will change to pH 5.60 8.90 9.13 9.32 Cant be determined

5.60

If the Ka of an acid is 1.38 *10^7, what is the pKa?

6.86

If the pH is 5 what is the pOH?

8.5

Hydrophobic interactions make important energetic contributions to Bunding of hormone to receptor protein Enzyme substrate interactions Membrane structure 3D folding of polypeptide chain All of the above

All of the above

When water is found in a crystal structure of a biomolecule, which statement is NOT true?

All of the above are true

Which diagram illustrates clustering of lipids A, B, neither A or B, both A and B

B

A compound is known to have a free amino group with a pKa of 8.8, and one other ionizable group with a pKa between 5 and 7. To 100 mL of a 0.2 M solution of this compound at pH 8.2 was added 40 mL of a solution of 0.2 M hydrochloric acid. The pH changed to 6.2. The pKa of the second ionizable group is: A) The pH cannot be determined from this information. B) 5.4 C) 5.6 D) 6.0 E) 6.2

C. 5.6

Which compound results in the formation of clathrate structure?

CH4

Carbon dioxide, produced by glucose oxidation, is not very soluble. How does the body transport this molecule through blood to be exhaled from lungs?

CO2 can be converted to the more soluble HCO3 for transport.

Which diagram illustrates amphipathic molecule

COOH bond. Long chain

Which of the following would have the GREATEST effect on osmotic pressure? NaCL CaCL2 Glucose Sucrose All of the above

CaCl2

Which statement does not describe strategy used by multicellular animals to maintain osmotic balance with their surroundings

Cells have contractile vacuole, an organelle that pumps water out of cell

Dissolved solutes alter some physical properties of the solvent water because they change

Concentration of water

list bond interaction in decreasing order( strongest to weakest) hydrogen bond, covalent bond, ionic bond, van der Waals interaction

Covalent bond, ionic bond, hydrogen bond, van der waals interaction

A compound has a pKa of 7.4. To 100 mL of a 1.0 M solution of this compound at pH 8.0 is added 30 mL of 1.0 M hydrochloric acid. The resulting solution is pH: A) 6.5 B) 6.8 C) 7.2 D) 7.4 E) 7.5

D. 7.4

Consider an acetate buffer, initially at the same pH as its pKa (4.76). When sodium hydroxide (NaOH) is mixed with this buffer, the: A) pH remains constant. B) pH rises more than if an equal amount of NaOH is added to an acetate buffer initially at pH 6.76. C) pH rises more than if an equal amount of NaOH is added to unbuffered water at pH 4.76. D) ratio of acetic acid to sodium acetate in the buffer falls. E) sodium acetate formed precipitates because it is less soluble than acetic acid.

D. ratio of acetic acid to sodium acetate in the buffer falls.

Which property of water has had the MOST profound consequence for aquatic organisms? Water has high specific heat. Water has high heat of vaporization. Due to hydrogen bonding, solid water is less dense. Water has a high melting point. Nonpolar molecules are poorly soluble in water.

Due to hydrogen bonding, solid water is less dense than liquid water.

Comparing two molecules to the right, which statement is true Ephedrine, Epinephrine

Ephedrine can pass easier through membrane

Phosphoric acid is tribasic, with pKas of 2.14, 6.86., and 12.4. The ionic form that predominates at pH 3.2 is

H2PO4

Which statement describes the forces that drive Michelle formation from amphipathic molecules, such as fatty acids dissolved in water?

Head groups of the molecules are exposed on the outer surface of the michelle, minimizing the order surrounding solvent molecules

Which result influences the lower limit for an atoms Van Der walls radius

The electron clouds begin to repel each other

Properties of Aqueous Solutions

Hydrogen bonds form readily in aqueous solutions

What is the correct terminology for reactions A and B in the diagram

Hydrolysis, Condensation

Which statement about hydrogen bonds is NOT true? Hydrogen bonds account for the high boiling point of water. In liquid water, average water molecule forms hydrogen bonds with 3 to 4 water molecules. Individual hydrogen bonds are much weaker than covalent bonds. Individual hydrogen bonds in liquid water exist for many seconds and sometimes for minutes The strength of a hydrogen bond depends on the linearity of the three atoms that involved in the bond.

Individual hydrogen bonds in liquid water exist for many seconds and sometimes for minutes

Camels live in very dry habitats and do not need to consume water as frequently as animals in wetter habitats. What is a partial reason for this?

Metabolic water is produced by oxidation of fuels such as glucose.

Ibuprofen Example : If stomach pH is about 1.5 and small intestine pH is about 6. Where will more ibuprofen be absorbed

More ibuprofen will be absorbed in small intestine because it will be uncharged due to the pH being greater than the pKa

Biologically important gases

O2 and CO2 are both non polar molecules and are therefore both poorly soluble in water

The ionization of water is due to the strongly electronegative element

Oxygen receiving an electron from hydrogen

The high degree of cohesion of water molecules influences which process? Plants can transport dissolved nutrients from roots to leaves. Water can combine with CO2 to form glucose. Loss of water causes lettuce leaves to wilt. Water is split by the energy of sunlight. Water can be used as a product in respiration.

Plants can transport dissolved nutrients from roots to leaves.

Which diagram shows hydrogen bond?SKIP

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Which statement regarding long-chain fatty acids in aqueous solution is not true?

The driving force of solubilizing fatty acids is increasing entropy of the fatty acid

Which statement doesn't describe a reaction that water can act as a heat buffer for cells and organisms? Water has high specific heat. Water has extended hydrogen-bonding network. Water can auto-ionize. A large amount of heat is required to raise the temp of water by 1 degree. All of statements describes reasons that water can act as a heat buffer.

Water can auto-ionize.

The pH of a sample of blood is 7.4, while gastric juice is pH 1.4. The blood sample has:

one million times lower H than gastric juice

Water can act as ________ in biological reactions

a solvent, reactant and product

You want to maintain pH=7.0 for enzyme reaction that will produce hydrogen ions along with the desired product. At equal concentrations, which weak acid if any will serve as a better buffer? Acid a pKa= 6.5, Acid B pKa= 7.5

acid A

A true statement about hydrophobic interactions is that they: A) are the driving force in the formation of micelles of amphipathic compounds in water. B) do not contribute to the structure of water-soluble proteins. C) have bonding energies of approximately 20-40 Kjoule per mole. D) involve the ability of water to denature proteins. E) primarily involve the effect of polar solutes on the entropy of aqueous systems.

are the driving force in the formation of micelles of amphipathic compounds in water.

Which process would NOT disrupt the weak interactions between two biomolecules in solution

cooling the solution

Biological buffering systems include

histidine, bicarbonate, and phosphate

Which force plays the greatest role in stabilizing biological structures in membranes?

hydrophobic interactions that increase solvent entropy

If person is suffering from acidosis, which treatment would NOT be wise?

hyperventilation

Dissolving a nonpolar solute in water _________ the order of the solvent and _____ the dynamic interplay among water molecules that occurs in pure water

increases, decreases

Ice is _____ than water because ________

less dense, frozen water maintains more hydrogen bonds

Three buffers are made by combining a 1 M solution of acetic acid with a 1 M solution of sodium acetate in the ratios shown below. 1 M acetic acid 1 M sodium acetate Buffer 1: 10 mL 90 mL Buffer 2: 50 mL 50 mL Buffer 3: 90 mL 10 mL Which of these statements is true of the resulting buffers?

ph of buffer 1 > ph of buffer 2> ph of buffer 3

In which reaction does water NOT participate as a reactant?

production of gaseous carbon dioxide from bicarbonate

Henderson-Hasselbalch equation

relates the pH of a solution to the pKa and the concentrations of acid and conjugate base.

Proton hopping essentially means that

several protons move between hydrogen bonded water molecules causing net movement of photon over a long distance in short time

When two atoms are joined together covalently, radius of atoms in the covalent bonds are __________ than the radius of the atoms alone because the joined atoms are ______

shorter, pulled together by the shared electron pair

Hydrogen bonds are not

strongest when the oxygen atom is perpendicular to hydrogen donor

Which property of water does NOT contribute to the fitness of the aqueous environment for living organisms

the very low molecular weight of water