General Chemistry Problem - Conversions

[skyisblue]

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This problem is all about conversions. I've done it many times, but I still don't get the right answer. I'm thinking the book could be wrong, but I need to concur with a few people first. Here goes:

A technician used a section of glass tubing to measure the density of a liquid that the laboratory needed to identify. The inside diameter of the tubing was known to be 0.87mm. An empty piece of the tubing weighed 0.785g. When liquid was drawn into the tubing to a height of 4.0cm, the tubing and liquid weighed 0.816g. Find the density of the liquid in g/cm cubed.

Please help guys!

 

[student253]

mass of liquid = .816-.785 = .031 g
volume = Pi x r^2 x h = Pi x (.87/2 x 1 cm/10 mm) x 4.o cm = .5466 cm^3

Density = g/cm^3 --> .031g/.5466 cm^3 ==> .0567 g/cm^3

Hope this helps... do you happen to have the right answer?

 

[skyisblue]

mass of liquid = .816-.785 = .031 g
volume = Pi x r^2 x h = Pi x (.87/2 x 1 cm/10 mm) x 4.o cm = .5466 cm^3

Density = g/cm^3 --> .031g/.5466 cm^3 ==> .0567 g/cm^3

Hope this helps... do you happen to have the right answer?

We both got the same answer! I believe the book is wrong. According to book, the answer is 1.3g/cm cubed.

Did you square the radius??

 

[skyisblue]

mass of liquid = .816-.785 = .031 g
volume = Pi x r^2 x h = Pi x (.87/2 x 1 cm/10 mm) x 4.o cm = .5466 cm^3

Density = g/cm^3 --> .031g/.5466 cm^3 ==> .0567 g/cm^3

Hope this helps... do you happen to have the right answer?

OH SHOOT the book is right! We forgot to square the radius. When that is done, it comes out to be 1.3

 

[student253]

Ooops, don't forget that on the DAT!!!