Question

The Half Life of Caffeine is 5.

4. Go online and find the amount of caffeine in your favorite caffeinated beverage. Whether it is a Starbucks coffee or latte, a soda, or an energy drink. List that amount here. Beverage: Latte from Dunkin Donuts Amount of caffeine: 97 mg Source: Assume you have that drink at the start of our class. a. At what time will you have half of the original amount in your system? Based on your drink, how much caffeine will be in your system at that time? b. Will you still feel the effect of the caffeine when you go to sleep? (i.e. will the caffeine be reduced to an amount that it should no longer have any stimulant effect on your body?) Explain why or why not.

Answer 1

a. Half-life refers to the time period at which the quantity of the substance is halved.

Given that the quantity of caffeine is 97mg and the half life of caffeine is 5 hours.

So 5 hours after the start of the class, I will have half of the original amount in my system. Based on my drink, I will have around 48.5mg in my system at this time.

b. If my class starts at 8 am, then by the time I sleep it is already 12 am. So it is about 15 hours. So by 15 hours , I will have 12.125 mg of caffeine in my system. I don't think it will have any effect in my body since such a small amount is not significant enough to have any stimulant effect on my body. In general, the effect of caffeine peaks between 15-45 mins after intake. So given this time, I don't think it will have any effect after 15 hours.