Question

Glycerin, of density 1260.0 kg/m3, is poured into an open U-shaped tube. Ethyl alcohol, of density 790.0 kg/m3, is then poured into one arm until the height of the alcohol column is 21.4 cm. The two liquids do not mix. What is the difference in height between the top surface of the glycerin and the top surface of the alcohol?

Answer 1

The height of the columns must weigh the same to be in equilibrium.
What is the weight of 21.4cm of ethanol?

weight= height*area*density*g
set that equal to the weight of the glycerol, and you have the height of the glycerol.

Answer 2

how do you find the area?

Answer 3

notice area is on both sides of the equation, it will divide out if the area of the tube is constant.

Answer 4

1260 kg/m^3 x 9.8m/s^2 x 0.241m = 790kg/m^3 x 9.8m/s^2 x h

h = 0.384m

difference = 0.384 - 0.214 = 0.170 m

this answer was incorrect. what am i doing wrong?

Answer 5

hmmmm.
Ok, then the rationale is wrong. Some of the glycerol is on the alcohol side.
weight of glycerol side= weight of ethanol side, but some of the glycerol is on the alcohol side to do that.

thinking. give me a few minutes.

Answer 6

Let me see if I can get some other thinking here....again, a few minutes.

Answer 7

Ok, I am officially stuck. My mind is not working. I will try to return again on this.

Answer 8

okay...no problem

Answer 9

it worked for me. but, i had to subtract the answer i got for the height from the provided height.