7th grade - Extra credit

Good afternoon everyone!

Again, here I have some extra credit problems for you. All you have to do is copy these problems into a word document, print it out and THEN solve. Remember you must explain your reasoning (process).
This is not mandatory, however, if you wish to make up for some missing points (such as the ones on the quiz) this is your chance. You have until Thursday January 26th, 2012.

Enjoy!

1. Mt. Everest, the highest elevation in Asia, is 29,028 feet above sea level. The Dead Sea, the lowest elevation, is 1,312 feet below sea level. What is the difference between these two elevations?


2. In Buffalo, New York, the temperature was ^-14°F in the morning. If the temperature dropped 7°F, what is the temperature now?


3. A submarine was situated 800 feet below sea level. If it ascends 250 feet, what is its new position?


4. Roman Civilization began in 509 B.C. and ended in 476 A.D. How long did Roman Civilization last? 


5. Metal mercury at room temperature is a liquid. Its melting point is ^-39°C. The freezing point of alcohol is ^-114°C. How much warmer is the melting point of mercury than the freezing point of alcohol?