I had an aluminum slug that I measured the mass of as 8.669g.
The length was 2.8cm
The diameter was .950 cm
The volume (using a volumetric cylinder) was 3.5cm^3^. We are supposed to do a calculated volume using (pi*r^2*h) also..but when I do it with the formula, it doesn't come out the same both ways. I think I'm following everything, but it's just not coming close to being equal. Am I doing something wrong, or did we (more than likely) not measure something right?
2006-09-14 09:55:15 · 2 answers · asked by buttercup1137 2 in Science & Mathematics ➔ Chemistry
EDIT..sorry. That's the RADIUS I gave. The radius is .950, not the diameter. :)
2006-09-14 10:16:37 · update #1
Half the diameter squared is .2256pi or .709. That times the length gives 1.98 cm^3 or 2.0 cm^3 (because the length is only expressed as 2 significant figures).
This is pretty far from 3.5 cm^3. Don't know why that is, unless the thing is hollow. Since aluminum has a density of 2.7 g/cm^3, the volume of an 8.669 g aluminum object should measure to 3.2 cm^3. This is between your calculation and the measurement, but is closer to the measurement.
2006-09-14 10:06:23 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Apparently you had a closed cylinder to measure the volume with.. in that case you need to modify the formula to adjust for the upper and lower ends..
i.e : (pi x r^2 x h)+ 2(pi x r^2)
(add cylinder + 2 circular ends )
this gives the volume as 3.401 (quite near to measured value)
but just confirm that u had a closed cylinder there then..
2006-09-14 17:18:17 · answer #2 · answered by Shariq M 5 · 0⤊ 0⤋