Specific heat capacity

[Primarygun]

Does the specific heat capacity of an object affect the rate of transfer of energy from an object to another?

For instance, alcohol has a lower specific heat capacity than water.

If they are both at 50 degree Celsius and poured into a beaker containing water of 20 degree Celsius respectively, after 1 second, in which beaker, much heat is transferred?

 

Thanks for kind attention.

[DQW]

Does the specific heat capacity of an object affect the rate of transfer of energy from an object to another?

In general, no. HOwever, it does affect the rate at which temperature chenges. The time consdtant for thermal changes goes like C/K, where c is the heat capacity and K is the thermal conductivity (make sure the units of the ratio are those of time). The reason is obvious : it takes more heat to produce the same change in temperature, the greater is C (and hence it takes more time at a given heat transfer rate). The heat transfer rate itself depends only on temperatures, geometries and thermal constants whose units possess a factor of time in them : such as the thermal conductivity, the emissivity, the convective heat transfer coefficient, etc.

 

For instance, alcohol has a lower specific heat capacity than water.

If they are both at 50 degree Celsius and poured into a beaker containing water of 20 degree Celsius respectively, after 1 second, in which beaker, much heat is transferred?

It is unclear what you are talking about here. If the beaker is well insulated, one assumes that there is no heat loss out of the beaker, and energy conservation then tells us that the heat lost by the hotter liquid is gained by the colder liquid. So, as such there's onlt heat transfer between the two liquids in the beaker. To monitor the rate of heat transfer, one must combine the liquids without mixing and measure the time for thermal homogenization - for the temperature to become uniform within the liquid.

 

As explained above, this will happen faster in the case where the heat capacity of the liquid is lower (pouring in hot alcohol). But this does not mean the the heat transfer is quicker too. In fact, since the time constant for temperature change scales like the the heat capacity, C, and so does the heat transferred, the time constant for heat transfer is actually independent of C.

 

If that last bit wasn't clear, think of the rate of change, which is inversely proportional to the time constant.

 

[math]\frac {d \theta}{dt} ~~\alpha~~1/C [/math]

 

[math]\Delta H ~~\alpha ~~C \Delta \theta~~\implies~~\frac {dH}{dt}~~\alpha~~C \frac {d \theta}{dt} ~~\alpha~~C/C =1 [/math]

[Primarygun]

Thank you