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Biochem Exam 1 > Chapter 2 - Water > Flashcards

Chapter 2 - Water Flashcards

1
Q

What are the fluid phases of water?

A

Gas (steam/vapor)
Liquids (Water)

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2
Q

What are the condensed phases of water?

A

Liquids (water)
Solids (ice)

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3
Q

Name 5 reasons why water is essential for biochemistry.

A
  1. Medium for most biochemistry reactions (transportation - taking meds)
  2. Common reactant
  3. Part of cellular components (protein, cell membrane)
  4. Covers 70% of earth’s surface
  5. Helps maintain body temperature (sweat, we dont freeze in cold)
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4
Q

In which phase are molecules easy to observe??

A

gas phase - they’re far away

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5
Q

Gasses are measured under what conditions??

A

Standard temperature and pressure (1atm, 0 degrees celsius)

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6
Q

Water has a high ______

A

specific heat, boiling point

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7
Q

What is the essential feature of the gas phase?

A

There is effectively no interaction with other molecules

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8
Q

Properties of gasses are essentially the same, as long as they are under_____

A

STP

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9
Q

A water molecule is ______overall

A

neutral

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10
Q

A perfect tetrahedral conformation is _______degrees, but water is ______degrees due to ______

A

A perfect tetrahedral conformation is 109.5 DEGREES, but water is 104 DEGREES due to the lone pairs on oxygen

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11
Q

How many valence electrons does oxygen have?

A

6

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12
Q

In a covalent bond, sharing is usually ______

A

unequal

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13
Q

The only time when electrons are shared completely equally in a covalent bond is when…?

A

covalent bond between identical atoms (N2 or O2)

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14
Q

Unequal sharing of electrons leads to _______

A

partial charges

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15
Q

The electronegativity scale runs from ____to____

A

0 to 4

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16
Q

On the periodic table, which elements are the most electronegative??

A

The elements at the top right of the periodic table

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17
Q

Is CO2 polar or nonpolar? why?

A

nonpolar because the vectors cancel each other out

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18
Q

What are the 2 INCOMPRESSIBLE states of water? What does this mean?

A

solid and liquid. the external pressure causes the molecules to not be able to move closer together

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19
Q

Are hydrogen bonds covalent bonds?

A

NO

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20
Q

On their own, hydrogen bonds are _____

A

weak

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21
Q

Together, hydrogen bonds form a very strong lattice structure. What does this explain about water?

A

Its peculiar properties

22
Q

As water freezes to ice, its density…..

A

DECREASES

23
Q

As ice melts to water, density…?

A

increases

24
Q

At what temperature does water reach its maximum density?

A

4 degrees celsius

25
Q

The uniqueness of water stems from which 2 things?

A

electronegativity difference (large)
and the geometry of its hydrogen bond interactions

26
Q

The process of surrounding ions with water molecules is called…?

A

hydration

27
Q

What is specific heat?

A

The amount of energy needed to increase the temperature of 1 gram of a substance by 1 degree celsius

28
Q

Water acts as a _________

A

temperature buffer. heat loss or gain is smaller in water compared to other substances

29
Q

As temperature of water increases, the H bonds _____ but dont _____

A

bend but dont break

30
Q

Which phase of water does NOT have a high specific heat?

A

ICE. The H bonds cannot bend in this phase

31
Q

What is the definition of an acid?

A

Species that increase the hydrogen ion concentration when added to water

32
Q

What are bases?

A

Species that DECREASE the hydrogen ion concentration when added to water

33
Q

NaCl dissolves in water to form a ______ solution

A

neutral

34
Q

NH3 is a _____?

A

weak base

35
Q

ph=

A

-log[H+]

36
Q

What is the pH of the blood?

A

7.4

37
Q

pka=

A

-logka

38
Q

The flat region on a titration curve is known as the ____________ and is the numeric value of _______

A

buffering region, pka

39
Q

All weak acids and bases are _______

A

buffers

40
Q

What is the most significant physiological buffer?

A

blood bicarbonate buffer

41
Q

CO2 is technically a(n)____

A

acid

42
Q

What is 3 mol in avagadro’s number??

A

18 * 10^23

43
Q

A chemical is more stable when it contains ______energy

A

less

44
Q

Low pka = ____aciditiy

A

HIGH

45
Q

low ka = ___Acidity

A

LOW

46
Q

At what temperature does water have the smallest VOLUME

A

4/5 degrees celsius

47
Q

Water can be considered a ____ of oxygen

A

hydride

48
Q

Why does decane have a slight affinity for water?

A

induced dipole attraction

49
Q

Does a substance NEED to provide OH- to be considered basic?

A

NO

50
Q

What is the pH of our stomach acid when we’re hungry?

A

1-2

51
Q

If pH is 5 what is the [H+] ion concentration?

A

0.00001 mol/L

Biochem Exam 1 (7 decks)

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