Final Exam Answers

I gave my final exam this past week. I had students tell me they thought it was difficult, but the average was a B so I figured it wasn't too bad. As usual, the TAs and I had some entertainment reading some of the answers.

1. Carbon-14 Dating is a way to determine the age of archaeological artifacts. The artifacts cannot be older than about 60,000 years. Why?

Because there was a flood then and that throws the system off.

(The answer is because C-14's half life is only about 60,000 years, but I had several list The Flood as the reason. I guess I had some young-earth theorists in my class.)

2. Why is radioisotope dating not as accurate after the 1940’s?

Because the way we do it now is not as correct as we did then with our radioisotope machine.

(The answer is because since the 1940's, there is an increase amount of radiation on the Earth due to atomic bombs, nuclear power plants, etc. Many students wrote about the "radioisotope machine" - not sure where they pulled that one from.)

3. Pictured below are Vitamins A and C. Why is Vitamin A soluble in fat, but Vitamin C is soluble in water? (HINT: Remember our discussion about solubility, “like dissolves like”, and the molecular structure).

Vitamin A is soluble in fat because it is insoluble and is fat. Since they are both insoluble they dissolve each other. Vitamin C is soluble in water because it is soluble and water is soluble so they dissolve in each other.

or

Vitamin A is soluble in fat, and Vitamin C is soluble in water.

(Like these students, I had many answer a question by rewording the question in a declarative matter.)

4. Write a balanced equation for hydrochloric acid and the base calcium hydroxide.

Mrs. Nichols I just don't know about all this chemistry, just isn’t my subject…actually I don’t believe any subject at this college is my subject. I did enjoy your class. I attended every time the doors were open and met a lot of pretty girls. Thank you for being a great teacher. Happy Holidays.

(You've probably guessed: this was from my student who liked to write little anecdotes on all his exams - see prior posts for another one about Michael Jordan and making a polyester.)