Question

E. Sodium-24 (t - 15 h) is used to study blood circulation. If a patient is injected with an aqueous solution of 2*NaCl that has an activity is 2.5x10° d/s (disintegrations per second). Given hat the disintegration of "Na follows first order kinetics, how much of the activity is present in he patient's blood after 4.0 days

Answer 1

Na-24 half life = 15h

We know that for first order reaction

$t\frac{1}{2} = \frac{0.693}{K}$

Therefore, K = $\frac{0.693}{t\frac{1}{2}}$

K= $\frac{0.693}{15h}= 0.0462h^{-1}$

At starting, (Activity)₀ = 2.5x10⁹d/s

At 4days, 4×24hr= 96hr

96×2.5×10⁹

= 2.4×10¹¹ d/s