The rate of a first-order reaction is followed by spectroscopy, monitoring the absorbance of a colored reactant at 520 nm. The reaction occurs in a 1.00-cm sample cell, and the only colored species in the reaction has an extinction coefficient of 5.60 * 103 M-1 cm-1 at 520 nm. (c) Calculate the half-life of the reaction.

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Hi, everybody. Here's our next question. What characteristic appearance do some lymphatic vessels have due to the presence of valves, a spiral pattern b bulging or beaded appearance, c straight and smooth walls or D star shaped branching. So let's think about these valves and lymphatic vessels. They need valves just like veins because they're draining lymphatic fluid away from the peripheral tissues and up to the central part of the body. So valves help to prevent back flow just as they do in the veins. But imagine these rather small lymphatic vessels, you have valves that are close together and that produce these bulges in the walls of the lymphatic vessels. So imagine a grouping of these bulges along the line of your limbo vessel. And you can see that you would end up with choice B A bulging or beaded appearance due to the presence of valves. Let's look at our other answer choices. Just to understand why they're not correct choice. A spiral pattern would not be a result of these bulges in the valve walls. So not a correct answer. Lymphatic vessels are not found in spirals. So I see straight and smooth walls. Well, this is true about limbo vessels. They have straight and smooth balls, but this is not responsible for their bulging appearance. And the straight and smooth balls are not a result of the presence of valves as our question asked. So choice c not our correct answer. And finally to D star shaped, branching, branching. Well, just like blood vessels, lymphatic vessels. If you look at them as like a tree or a root system, you'd see them branching into smaller and smaller diameter of vessels as you move into more peripheral tissues. But this is not because of valves. This is just its design to collect the fluid from the capillaries with very small lymphatic vessels and then drain them into the larger vessels and then trunks. So choice d not our correct answer. And so once again, the characteristic appearance of some lymphatic vessels that is due to the presence of valves is choice b bulging or beaded appearance. See you in the next video.

Verified Solution

Key Concepts

First-Order Reactions

Absorbance and Beer-Lambert Law

Half-Life of a Reaction