Suppose glucose and hemoglobin are diffusing in water. A small amount of each is released simultaneously. How much time (in s) passes before the glucose is 8.30 s ahead of the hemoglobin? Such differences in arrival times are used as an analytical tool in gas chromatography.

Respuesta :

Given:

Time = 8.30 s ahead of the hemoglobin

For the equation of both glucose and hemoglobin:

[tex]\begin{gathered} \sqrt{2D_gt_g}=\sqrt{2D_h(t_g+\Delta t)} \\ \\ D_gt_g=D_h(t_g+\Delta t) \\ \\ D_gt_g=D_ht_g+D_h\Delta_t \end{gathered}[/tex]

Rewrite the equation for tg:

[tex]\begin{gathered} D_gt_g-D_ht_g=D_h\Delta_t \\ \\ t_g(D_g-D_h)=D_h\Delta_t \\ \\ t_g=\frac{D_h\Delta_t}{D_g-D_h} \\ \\ \end{gathered}[/tex]

Where:

Dh is the diffusion coefficient of hemoglobin = 6.9 x 10⁻¹¹ m²/s

Dg is the diffusion coefficient of glucose = 6.7 x 10⁻¹⁰ m²/s

Δt = 8.30 seconds

Substitute these values for the variables in the equation and solve:

[tex]\begin{gathered} t_g=\frac{6.9\times10^{-11}*8.30}{6.7\times10^{-10}-6.9\times10^{-11}} \\ \\ t_g=\frac{5.727\times10^{-10}}{6.01\times10^{-10}} \\ \\ t_g=0.953\text{ seconds} \end{gathered}[/tex]

Therefore, the time that passes before the glucose is 8.30 s ahead of the hemoglobin is 0.953 seconds.

ANSWER:

0.953 seconds