A package of aluminum foil contains 50. ft2 of foil, which weighs approximately 9.0 oz . Aluminum has a density of 2.70 g/cm3. What is the approximate thickness of the foil in millimeters?
Express your answer to two significant figures and include the appropriate units.
Please help me this?
2018-01-08 6:51 pm
回答 (3)
2018-01-08 7:26 pm
1 oz = 28.35 g
Mass of the foil = (9.0 oz) × (28.35 g/oz) = 9.0 × 28.35 g
Density of the foil = 2.70 g/cm³
Volume of the foil = (9.0 × 28.35 g) / (2.70 g/cm³) = 9.0 × 28.35 / 2.70 cm³
1 ft² = 929 cm²
Area of the foil = (50 ft²) × (929 cm²/ft²) = 50 × 929 cm²
Thickness of the foil = (9.0 × 28.35 / 2.70 cm³) / (50 × 929 cm²) = 0.0020 cm = 0.020 mm
Mass of the foil = (9.0 oz) × (28.35 g/oz) = 9.0 × 28.35 g
Density of the foil = 2.70 g/cm³
Volume of the foil = (9.0 × 28.35 g) / (2.70 g/cm³) = 9.0 × 28.35 / 2.70 cm³
1 ft² = 929 cm²
Area of the foil = (50 ft²) × (929 cm²/ft²) = 50 × 929 cm²
Thickness of the foil = (9.0 × 28.35 / 2.70 cm³) / (50 × 929 cm²) = 0.0020 cm = 0.020 mm
2018-01-08 9:25 pm
since this is chemistry class.. how about we use that dimensional analysis you've been practicing?
.. 9.0 oz.. . 1 lb.. ... 454 g... .1 cm³.. . 10 mm......(1 ft)²... ... ... .(1 in)²
---- ----- x ---- --- x ---- ---- x ---- --- x ----- ---- x --- ---- --- x ---- ---- ---- = 0.020 mm
.. 50.ft².. ..16 oz.. . .. 1 lb.... .2.70g.. .. 1 cm.. ... (12 in)².. .. (2.54 cm)².
just enter
.. 9 / 50 / 16 * 454 / 2.70 * 10 / 12² / 2.54²
in your calculator and round to 2 sig figs.
*******
folks... we teach factor label method (aka dimensional analysis) to chemistry students for a number of very good reasons. If you don't know it, you need to learn it before you go about helping others. You can google it, open a chemistry textbook, or I cover it here. however you do it, do learn it.
https://answers.yahoo.com/question/index?qid=20160219172026AAr3J7B
.. 9.0 oz.. . 1 lb.. ... 454 g... .1 cm³.. . 10 mm......(1 ft)²... ... ... .(1 in)²
---- ----- x ---- --- x ---- ---- x ---- --- x ----- ---- x --- ---- --- x ---- ---- ---- = 0.020 mm
.. 50.ft².. ..16 oz.. . .. 1 lb.... .2.70g.. .. 1 cm.. ... (12 in)².. .. (2.54 cm)².
just enter
.. 9 / 50 / 16 * 454 / 2.70 * 10 / 12² / 2.54²
in your calculator and round to 2 sig figs.
*******
folks... we teach factor label method (aka dimensional analysis) to chemistry students for a number of very good reasons. If you don't know it, you need to learn it before you go about helping others. You can google it, open a chemistry textbook, or I cover it here. however you do it, do learn it.
https://answers.yahoo.com/question/index?qid=20160219172026AAr3J7B
2018-01-08 7:17 pm
What's the problem here?
With mass and density you clearly know how to find volume.
And with volume and area you clearly know how to find thickness.
It is two steps.
Of course we will need units that match. Let me google that for you.
1 oz = 28.35 g
Then 9 oz = 255.15 g
1 ft = 30.48 cm
1 ft^2 = (30.48 cm)^2 = 929.03 cm^2
Then 50 ft^2 = 46,451 cm^2
Volume = mass / density
Thickness = volume / area
To convert from cm to millimetres multiply by 10.
With mass and density you clearly know how to find volume.
And with volume and area you clearly know how to find thickness.
It is two steps.
Of course we will need units that match. Let me google that for you.
1 oz = 28.35 g
Then 9 oz = 255.15 g
1 ft = 30.48 cm
1 ft^2 = (30.48 cm)^2 = 929.03 cm^2
Then 50 ft^2 = 46,451 cm^2
Volume = mass / density
Thickness = volume / area
To convert from cm to millimetres multiply by 10.
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