Please help me with these "mole" problems..show all work?

Question

1. How many moles of pencil marks can you make in one minute?
2. If the surface area of the pacific ocean is 1.6576 * 10^8 km^2 and the average depth is 4028 meters, how many moles of water are in the pacific. (hint:18 cm^3 = 1 mole H2O)
3. If the average penny is 2mm thick, how close to the sun would a 1 mole stack of pennies reach? (google distance to the sun watch your units)

please help...and show all the work...thank you very much.

Answer 1

I always had to do my own homework...

It's one thing to ask a question about it, but to "Show all the work?" That's just plain lazy.

Answer 2

1 is a practical exercise, no way to calculate it from this info. What you would have to do is accurately weigh a piece of paper. Then grab your pencil and start scribbling as fast as you can. Get it going a mole a minute... (sorry, couldn't resist the nasty bad pun). After scribbling furiously for exactly one minute reqweigh the piece of paper and determine the weight of the pencil marks. Assuming that your pencil lead is pure carbon, compare the weight of your pencil marks to the atomic weight of carbon (just divide). That will tell you how many moles of carbon pencil marks you have made.



2 is a unit conversion problem. Convert the numbers you are given from m to cm and from km^2 to cm^2. Use them to calculate the volume of the ocean in cm^3, then divide by 18 to get the number of moles of water.



3 is just multiplying. A mole of pennies is (like anything else) 6.0226 X 10^23 pennies. How many mm would that be? Compare that to how many mm it is from here to the sun.

Answer 3

1. I don't know how many pencil marks you can make in 1 minute. When you find out the number, divide 6.022 x 10^23 by the amount of marks



2. (165,760,000 x 4.028)100,000/18

I am too lazy to actually solve it but I set up the problem

depth times surface area converted into centemeters divided by 18



3. I don't know, just find the distance from earth to sun in kilometers and multiply by 1000 to get millimeters. then subtract

6.022 x 10^23 from the distance and you get your answer