Enter your answer in the provided box. many drugs decompose in blood by a first-order process. two tablets of aspirin supply 0.60 g of the active compound. after 30 min, this compound reaches a maximum concentration of 2 mg/100 ml of blood. if the half-life for its breakdown is 90 min, what is its concentration (in mg/100 ml) 2.5 h after it reaches its maximum concentration?

Question

Emma Cooley

Chemistry

15 January, 17:59

Enter your answer in the provided box. many drugs decompose in blood by a first-order process. two tablets of aspirin supply 0.60 g of the active compound. after 30 min, this compound reaches a maximum concentration of 2 mg/100 ml of blood. if the half-life for its breakdown is 90 min, what is its concentration (in mg/100 ml) 2.5 h after it reaches its maximum concentration?

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Crystal Mercado · Answer 1

First, we should get K, and we can get it from this equation:

K = ㏑ (2) / t1/2

when we have t1/2 (the half-life time) = 90 min so by substitution:

K = ㏑ (2) / 90 min

=0.0077

Then we can get C (the amount remains at time t) from this equation:

C = Ae^ (-Kt)

we have A (amount at t=zero) = 2 g / mL

& K = 0.0077 & t = 2.5 h, convert it to min 2.5*60 = 150 m

by substitution:

C = 2 * e^ (-0.0077*150)

= 2 * 0.315 = 0.63 g/mL