BioPHYSICAL chemistry

2.5 The ITC profile reflects the binding of the drug to the target.

2.6 A favorable drug candidate would have an ITC profile that changes

at low concentrations of the drug, reflecting a tight binding to the

target of interest.

2.7 Since the expansion is adiabatic, q=0. Since the external pressure

is constant, w=−PΔV=−(1 atm)(6 L) =−6 atmL=−606 J. The change

in the internal energy is the sum of the heat and work, or −606 J.

2.8

=−873.6 J

2.9 (a) The number of moles of carbon dioxide is 5 g/(44 g mol−^1 ) =

0.114 mol. The maximum pressure that can develop is:

(b) The final volume of the expanded gas is:

w=−PΔV=−(2.75 atm)(2.78 L −0.03 L) =−278 J

2.10

q=nCVΔT=(0.0409 mol)(25 J/(Kmol))(596 K−298 K) =305 kJ

The change in the internal energy is equal to the heat transferred

since no expansion work was performed.

2.11 The change in enthalpy will be 1.0 J.

2.12 The internal energy will not change.

2.13

For an ideal gas, the internal energy depends only upon the temper-

ature so the change in internal energy is zero. The change in internal

energy is the sum of the heat and work so the work is +5.76 kJ.

wnRT

V

V

nal

initial

=− ln^3 =−( 1 )( .8 314mol mmol) J/(KK

L

L

)( ) ln. 298kJ

4

2

=− 576

TT

P

nal initialP

nal

initial

3

==^32982

1

K

atm

atmm

= 596 K

Number of moles,

atm L

n

PV

RT

()()

.

==

11

0 08206

LLatm

Kmol

K

mol

⎛

⎝

⎜⎜

⎞

⎠

⎟⎟

=

()

.

298

0 0409

VV

P

nal initialP

initial

nal

3

3

(. )

.

== 003

92 6

L

33

1

278

atm

atm

= L.

P

nRT

V

(. ).

==

⎛

⎝

⎜⎜

⎞

⎠

0 114mol 0 08206 ⎟

Latm

Kmol⎟⎟

=

()

.

.

298

003

92 63

K

L

atm

wnRT

V

V

nal

initial

=− ln^3 =−(. 05 mol)(. 8314 J/((Kmol) K

L

L

)( ) ln303

20

10

442 ANSWERS TO PROBLEMS

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