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Chemistry

In: Novels

Submitted By ajam
Words 522
Pages 3
Opgave 1

a) Vis, at shikimsyres molare masse er 174,15 g/mol
Shikimsyre består af C7H10O5, heraf regnes molaremassen til

7*(12,01)+10*(1,08)+5*N(15,9)=174,37 g/mol

dette giver en difference på 0,22, hvilet er acceptabelt.

b) Tegn anethols to isomere former

c) Angiv reaktionstypen for reaktion 4 i biosyntesen for shikimsyre
I reaktion 4 i biosyntesen, bliver det dobbeltbundede O-atom, udskiftet med en OH-gruppe. Dette kaldes en substitutionsreaktion, da et atom udskiftes med e andet atom, i dette tilfælde udskiftes O med OH.

d)Argumenter for, at ethanol er et velegnet ekstraktionsmiddel ved udvinding af shikimsyre fra stjerneanis

e) Beremgn renhedsprocenten for shikinsyre

Til dette anvendes fælgende formel:

[pic]

Som omskrives til:
[pic]

Hvor der vides at: • [pic] er angivet til 0,100 M • [pic] er angivet til 21,5 mL • [pic] er angivet i forrige opgave til 174,15 g/mol

Tal indsættes:

[pic]

[pic]

Heraf opnås der, at der 0,375 g ren shikimsyre. Deraf skal masseprocenten regnes.
Dette sker med følgende formel:
[pic]

Heraf vides der at renhedsprocenten for shikimsyren er 93,8%.

f)Beregn pH for shikimsyren før titrering.

For at beregne pH-værdien før titreringen, anvendes til at starte med formlen for stofmængdekoncentrationen af ibuprofen:

[pic]

hvoraf:

• m er udregnet i forrige opgave til, 0,375 g • M er udregnet i opgave a til 174,15 g/mol • V er opgivet til 21,5 mL = 0,0215 L

Herefter indsættes tal og stofmængden udregnes

[pic]

Efterfølgende opstilles ligevægtsbrøken:

[pic]

[pic]

Hvoraf: • pKs: er aflæst til at være 5,19 dvs. 10-5,19 • C: vides at være 0,100 M

[pic]

[pic]

pH-værdien beregnes heraf til at være, 3,37 før titreringen.

g) Opskriv reaktionsskema for hydrolysen af oseltamivir i leveren

Opgave 2

a)Vis, at hydrolysen ved pH7,4 er af første orden med hensyn til parathion

For at en reaktion kan være af en 1.ordens reaktion, fælder det at sammenhængen mellem tiden og logaritmen er lineær. Dette undersøges ved, at plotte ln[pic] med tiden:

[pic]

Eftersom grafen viser en lineær regression mellem logaritmen og tiden, er det en 1. ordens regression.

b) Bestem hastighedskonstanten, k, ved pH 7,4

Opgave 3

a) Angiv den kemiske formel for nikkel(II)sulfid

Den kemiske formel for nikkel(II)sulfid er Ni(II)S, da Nikkel har 2 plus elektroner og Sulfid har 2 minus.

b)Beregn entalpitilvæksten for reaktionen:

Ni (s) + 4CO (g)[pic] Ni(CO)4 (g)

Herefter regnes entalpinværdierne

Ni (s)= 0
4CO (g)= 4*-110,53
Ni(CO)4 (g)= -607

Tal indsættes

[pic]=(0)+(4*-110,53)+(-607)= -1049,12 kj/mol

c) Vis, at entropitilvæksten for reaktionen er -404 j/mol*k. Argumenter for, at fortegnet er i overensstemmelse med forventningerne

Herefter regnes entroitilvæksten for følgende reaktion
Ni (s) + 4CO (g)[pic] Ni(CO)4 (g)

Ni (s)= 29,9
4CO (g)= 4*197,66
Ni(CO)4 (g)= 417

[pic]= (29)-(4*197,66)-(417)= -404 j/mol*K

d) Beregn den temperatur, T, hvor [pic]=0 kJ/mol
Til dette anvendes formlen

e)Beregn ligevægtskonstanten, K, ved 50C

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