The Math Forum

Ask Dr. Math - Questions and Answers from our Archives
Associated Topics || Dr. Math Home || Search Dr. Math

Volume, Mass, Density

Date: 9/14/96 at 12:24:45
From: Anonymous
Subject: Volume, Mass, Density

A flask that can hold 158g of water at 4 degrees Celsius can hold only
127g of ethyl alcohol.  What is the density of ethyl alcohol?

Okay, I know that ethyl alcohol is the same as grain alcohol, and my
chemistry book tells me that the specific heat capacity for GA is
2.4 J/(g*degrees C)  I'm trying to figure out if SH has anything to 
do with finding the density of GA!  Why else would they give me
the temperature, right?  I know the formula for density (d=m/v), and I 
know what to do if one of the pieces of info--mass, for example--is 
missing.  But I have no idea as to what to do with this problem. Maybe
I'm blind, or my brain isn't doing the right conversions, but I don't
see any volume here. I'm missing not one, but two pieces of 
information aren't I? What am I doing wrong?  Please help me!

Date: 9/14/96 at 21:38:29
From: Doctor Ana
Subject: Re: Volume, Mass, Density

You do need the volume to be able to solve this problem, but you 
should be able to figure it out from what you know. You can use the 
density of water at 4 degrees C to calculate how many mls of water are 
in 158g. Then you should be able to calculate the density of ethyl 
alcohol at 4 degrees C because you will know both volume and mass. 
This doesn't have anything to do with specific heat. This reason that 
they gave you the temperature was  because water (like everything 
else) changes density at different temperatures. So, be sure to look 
up the density of water (in any chemical handbook) at 4 degrees C. 

-Doctor Ana,  The Math Forum
 Check out our web site!   
Associated Topics:
High School Physics/Chemistry

Search the Dr. Math Library:

Find items containing (put spaces between keywords):
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

Math Forum Home || Math Library || Quick Reference || Math Forum Search

Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.