Question

Anyone know know how I can find the % of the piece I have cut (20.0 cm by 20.0 cm or 8 inch by 8 inch) in relation to the whole roll (area is 6.96 m^2)?

Answer 1

Find the area of the individual piece (in m2), divide by the total area. Percentage of the total area.

Answer 2

I need to find the cost PER ATOM of my sample aluminum foil (20.0 cm by 20.0 cm), which has a mass of 1.76 g. I found its number of moles: 0.0652 mol, and its number of atoms in the sample: 3.925 x 10^22. Is it good so far?

Answer 3

ohh.. so how do I find the total area of the sample? o.o

Answer 4

try length x width, in meters

Answer 5

oh. I am so stupid.

Answer 6

so basically convert 20.0 cm into metres, which is 0.2 m.

Answer 7

So the area of the sample is 0.4m^2, and the area of the whole roll is 6.96m^2. Not a very big percentage. Multiply that percentage by the cost per roll and you have the cost per sample

Answer 8

Divide the cost of the sample by the number of atoms, and you have the cost per atom.

Answer 9

:O THANK YOU SO MUCH JFRASER!!

Answer 10

So.. I got Area % = Area of sample/area of whole roll = 0.4 m^2/6.96 m^2 = 0.00574 m^2.

Cost per sample = Area % x Cost per roll = 0.0575 m^2 x $1.59 = $ 0.0914/m^2, and

cost per atom = Cost per sample/# of atoms = 0.0914 m^2/3.925 x 10^22 atom = 2.29299363 x 10^20...

So the cost per atom is 2.29 x 10^22? o.O ahh!!

Answer 11

please help!!

Answer 12

when you divide\[\frac{$0.0914}{3.925*10{^2}{^2}}\] you should gets some incredibly small #, not 10^20.If the whole roll only costs $1.59, a small fraction of that roll can't cost billions of times more money. You probably divided upside down.

Answer 13

ohh.. so wait is it going to be divided:

$0.0914
--------
3.925*10^22

= 2.29299363*10^-24... I'm so confused D; I'm so sorry!

Answer 14

that's the cost per atom of the aluminum.

Answer 15

it is? How? $2.29? o.o

Answer 16

don't ignore the exponent at the tail end of that number. it's not $2.29, it's $0.0000000000000000000000229

Answer 17

oh. is it really the cost? It looks weird for it to be cost.. o.o

Answer 18

that's the point. It's an incredibly small cost per atom, because you have an incredibly large number of atoms in the aluminum foil.

Answer 19

ohh.. so it's correct or wrong? D: ahh.