Help on chemistry problem

[Crank]

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Hey, if someone could help me out on this problem it would be greatly appreciated..

Question: Find the thickness of 75 square feet of aluminum foil weighing 340.2g, Al has density 2.70g/cm^3

 

[JamesBourne]

Hey, if someone could help me out on this problem it would be greatly appreciated..

Question: Find the thickness of 75 square feet of aluminum foil weighing 340.2g, Al has density 2.70g/cm^3

Sounds like a tricky problem, the way I solved it is first by figuring out the volume of the foil by doing simple math. 340.2 g / volume = 2.70 g/cm^3,
thus our volume should be 340.2 g / 2.70 cm^3 which comes out to be 126 cm^3. Okay, now we have volume and the given surface area, in order to find the volume, we do length * width * height. Since we know what length * width (surface area) is, we get the height by dividing volume (length * width * height) by surface area (length * width) length and width cancel out. We have to make sure we are on the same units, so we convert 75 ft^2 to cm^2 by multiplying 900 (30*30, rounding 1ft ~= 30cm), then divide volume (126 cm^3) by this number. The answer comes out to be around .002 cm. What was the answer?

 

[Crank]

its

1.8 x 10^-2mm

 

[rmm30]

would you mind sharing where this question came from?

 

[LaughingGas]

not 1.8 E-3?

 

[Moonie87]

Thickness= Volume/ Area

Volume:

340.2 g* 1cm^3/2.70g = 126 cm^3

Area:
(1 ft= 30.48 cm, so 1 ft^2=929.03 cm^2) (or you can covert to in^2 and then cm^2, answer is the same)

75 ft^2* 929.03 cm^2/1 ft^2 = 69677.28 cm^2

Thickness:

126 cm^3 / 69677.28 cm^2 = 0.001808 cm

0.001808 cm *10 mm/1cm = 0.01808 mm = 1.8 E -2 mm