Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

Liquid-Liquid Solution - Shrinkage and Estimation of Density

It is possible to estimate the density of a liquid-liquid solution from the density of the solute and the solvent. However, due to shrinkage, the estimate will be a bit too low.

Sponsored Links

Density (mass/volume unit) of solutions where both the solvent and the solute are liquids can be roughly estimated from density of the solute and the solvent by use of the formula:

Densitysolution = (x*ρ(solvent) + y*ρ(solute))/100      [1]

where
x =                wt% of solvent
ρ(solvent) = density of solvent
y =               wt% of solute
ρ(solute) =  density of solute

However, due to shrinkage, this will only be an estimate, with an error, varying with the concentration of the solute. The error is largest around 50 wt% concentration.
Concentration unit converter
Density of pure organic components: hydrocarbons, carboxylic acids and alcohols, sulphur compounds, nitrogen compounds and other common liquids.

Shrinkage is that the resulting density is higher than calculated by Eq [1], and occurs when molecules with relativele large difference in size are mixed. Then, the smallest molecules are placed in voids between the larger molecules, and the density increases.

The shrinkage will increase with an increasing difference in the molecule size of the solvent and solute. However, also effects other than size, as molecular shape and polarity, will influence on the shrinkage.

Examples showing the effect of shrinkage

At 20°C, the density of water is 0.9982 g/cm3 and the density of pure ethanol is 0.7893 g/cm3. For 20% ethanol, the density can be estimated using Eq [1]:

Density20% ethanol = (80[%]*0.9982 [g/cm3]+ 20[%]*0.7893[g/cm3])/100[%] =  0.9564 [g/cm3]

The same calculation is done for 50 and 70 wt% of ethanol, and the results and the difference from measured values are shown in the table below.

Mass% ethanol in water Density measured Density  estimated Difference in %
0 0.9982
20 0.9687 0.9564 1.27
50 0.9139 0.8938 2.20
70 0.8676 0.8520 1.80
100 0.7893

In the figure below, it is seen that with ethanol concentrations < 20% and > 70%, the estimated values are closer to the measured values.

The figure below shows the shrinkage for aqueous solutions of formic and acetic acids. It illustrates that the shrinkage is largest when the difference in molecular size is largest.

Sponsored Links

Related Topics

Related Documents

Sponsored Links

Share

Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.

Topics

Unit Converters

Temperature

oC
oF


Load Calculator!

Length

m
km
in
ft
yards
miles
naut miles


Load Calculator!

Area

m2
km2
in2
ft2
miles2
acres


Load Calculator!

Volume

m3
liters
in3
ft3
us gal


Load Calculator!

Weight

kgf
N
lbf


Load Calculator!

Velocity

m/s
km/h
ft/min
ft/s
mph
knots


Load Calculator!

Pressure

Pa (N/m2)
bar
mm H2O
kg/cm2
psi
inches H2O


Load Calculator!

Flow

m3/s
m3/h
US gpm
cfm


Load Calculator!

3 30

This website use cookies. By continuing to browse you are agreeing to our use of cookies! Learn more