Answer:
a)
[tex]K = 2.64 * 10^{-8}[/tex]
b)
[tex]15 \frac{5}{8}[/tex] hours
Explanation:
Given
Surface Area (S) of 250 grams of powder sample [tex]= 250[/tex] square meter.
[tex]S = 2500000[/tex] square centimeter
[tex]V\frac{dC}{dT} = 0.40[/tex] grams/minute
[tex]V\frac{dC}{dT} = \frac{dM}{dT} = \frac{0.40*60}{10} = 0.66[/tex] mg per second
[tex]C_s = 0.01[/tex] gram per cubic meter [tex]= 10[/tex] mg/ml
a)
[tex]\frac{dM}{dT} = K SC_s[/tex]
[tex]0.66 = K* 2500000* 10\\[/tex]
[tex]K = 2.64 * 10^{-8}[/tex] cm /sec
b) Time taken
Time taken to sink
[tex]\frac{10*60}{0.4} * 37.5 = 56,250[/tex]
Time in hours
[tex]15 \frac{5}{8}[/tex] hours