Skip to content

Latest commit

 

History

History
71 lines (51 loc) · 2.88 KB

27 - Determination of specific latent heat of fusion of ice using method of mixtures..md

File metadata and controls

71 lines (51 loc) · 2.88 KB
Raw
<iframe width="760" height="515" src="https://www.youtube.com/embed/gczb7jo9sa0?si=JKK7_YnDGATP0bt2" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>

  • Concept

  • Initial Setup

  • Measurements you need to take in the correct order.
  1. Measure the mass of the calorimeter with the stirrer. $M_1$ - ($M_c$)
  2. Fill the calorimeter with water and then measure the mass. $M_2$ - ($M_c +M_w$)
  3. Initial temperature of water $\theta_1$
  4. Get the lowest temperature after adding ice $\theta_2$
  5. Final mass of calorimeter + stirrer + ice $M_3$

Here $\theta_1 &gt; \theta_2$

A - Temperature of calorimeter + stirrer + water decreasing when ice cubes are added. B - 0C ice turning into 0C water. C - 0C water getting heated and coming into an equilibrium with water in the calorimeter.

After taking these readings, we can find the specific heat capacity of the ice using the equation $H = ML$ for the phase change of ice to water and we use $H =ms\theta$ for the other heat exchanges

So we assume that the heat gained from the ice cubes are equal to the heat released by the water and calorimeter

$$ \begin{align*} M_s =& Mass\ of\ ice\ added\ (M_3 - M_2) = Mass\ of\ water\ added\\ &(As\ the\ same\ ice\ is\ melt\ in\ to\ water)\\ M_w =& Mass\ of\ initial\ water\ in\ calorimeter\ (M_2 - M_1)\\ M_c =& Mass\ of\ the\ calorimeter\ +\ Stirer (M_1) \\\ L =& Spefic\ latemt\ heat\ of\ fussion\ of\ water\\ S_w =& Spefic\ heat\ capacity\ of\ water (4200)\\ S_c =& Spefic\ heat\ capacity\ of\ calorimeter(4000)\\ \\ H =& mS\delta\theta = ML \\ M_sL + M_sS_w(\theta_2 - 0) =& M_cS_c(\theta_1 - \theta_2) + M_wS_w(\theta_1 - \theta_2) \ \\ \therefore L =& \frac{(M_cS_c + M_wS_w)(\theta_1 - \theta_2) -M_sS_w(\theta_2 - 0) }{M_s} \end{align*} $$

Important point

  • Why should we use a net stirrer to stire this instead of a normal one?
As the density of ice is less than water ice floats on water. Therefore to keep them in the bottom we need a net stirrer

  • Why should we wipe the ice cubes with a blotting paper before adding it to the calorimeter?
To make sure its dry and no water is added with the ice cubes
  • Which shape of ice is best for this experiment?
small-medium cubes

Large onces can't be used as we can't mantain the temperature the calorimeter gains and it might  have a temperature difference between the surface and the inner temperature (inner could have a negative temperature)
Crushed or really small ice cubes can't be used as we can't blot them for water practically.