Chem II help?

[匿名]

2018-07-15 6:37 am

A critical reaction in the production of energy to do work or drive chemical reactions in biological systems is the hydrolysis of adenosine triphosphate, ATP, to adenosine diphosphate, ADP, as described by

ATP(aq) + H2O(l) ---> ADP(aq) + HPO2^4-(aq)

for which ΔG°rxn = –30.5 kJ/mol at 37.0 °C and pH 7.0. Calculate the value of ΔGrxn in a biological cell in which [ATP] = 5.0 mM, [ADP] = 0.70 mM, and [HPO42–] = 5.0 mM.

Could you also do the same problem again but use 0.20 for ADP instead of the 0.70?? Thank you!

回答 (1)

wanszeto

2018-07-15 10:03 am

ΔGrxn = ΔGrxn° + RT ln{[ADP][HPO₄²⁻]/[ATP]}

When [ATP] = (5.0 × 10⁻³) M, [ADP] = (0.70 × 10⁻³) M, and [HPO₄²⁻] = (5.0 × 10⁻³) M :
ΔGrxn
= (-30.5 × 10³) + (8.314) × (273 + 37) × ln{(0.70 × 10⁻³) × (5.0 × 10⁻³) / (5.0 × 10⁻³)} J/mol
= -49300 J/mol
= -49.3 kJ/mol

When [ATP] = (5.0 × 10⁻³) M, [ADP] = (0.20 × 10⁻³) M, and [HPO₄²⁻] = (5.0 × 10⁻³) M :
ΔGrxn
= (-30.5 × 10³) + (8.314) × (273 + 37) × ln{(0.20 × 10⁻³) × (5.0 × 10⁻³) / (5.0 × 10⁻³)} J/mol
= -52500 J/mol
= -52.5 kJ/mol

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