Why do tables of densities always include the temperature for which the listed values hold?

Question

What would be true of the densities of most solids and liquids at a temperature higher that the quoted one?

Answer 1

if the temperature changes so does the density. to get an accurate density calculation you use a gravimetric flask and an analytical balance. it depends on the substance as to if the density goes up or down with temperature flux.

Answer 2

The density of materials is temperature dependent. The temperature the material is at effects its density.

Density = mass / volume
Although a change in temperature will not effect the mass of the object, it is quite possible (and likely in many materials) to change the volume…even ever-so-slightly.
If the volume changes, the density changes, so it is important to know at what volume the measurements were take in the table you reference when comparing its value to your own situation.


Gasses are the most obvious and dramatic example of a density value depending on temperature. Gasses will readily expand/contract with a rising/lowering temperature. At STP, 1 mole of an idea gas has a volume of 22.4 Liters. Keeping the pressure constant but changing the temperature of the gas we see that the volume will increase with an increase in temperature (Charles Law),
V1 / T1 = V2 / T2
Solids and liquids, too, can expand/contract with temperature, although the change is less noticible.

Answer 3

Most compounds expand at higher temperatures (with the notable expansion of water below 4 degrees C- see anomalous expansion of water). Hence their densities decrease as temperature increases.

Solids expand only marginally as temperature increases, so assuming a particular density for all temperatures would not be a serious error, but liquids expands more readiily with increase in temp, and gases voraciously so; so for gases you'll have to use laws like the ideal gas law to calculate densities at different temperatures.

Answer 4

The density is dependent of temperature. Usually, solids and liquids are expanding their volume as temperature increase, so, density (think at formula) is decreasing. (For water, the smallest volume is at 4 degree Centigrade.)

Answer 5

Think about it- Water is the exception to the rule but, as an example it is easy to see in your environment. Water at 0 degrees is ice, which floats (less dense) than water that is a liquid, which is more dense than water that is vapor (gas state) right? So the temperature at which the density is recorded is very important!

Answer 6

They are listed for STP. At higher temps the gases would expand the most and then the liquids.Solids do not expand appreciably. D=m/v so increased volume would decrease density.

Answer 7

Density decreases when temperature increases. That's because thermal energy affects affinity forces between molecules.The molecules vibrate and they are diverged with result the forces of affinity decrease itself.