Question

cooling a sample of matter from 70°c to 10°c at constant pressure causes its volume to decrease from 873.6 to 712.6 cm3. classify the material as a nearly ideal gas, a nonideal gas, or condensed.

Answer 1

Explanation:

Expression for the coefficient of thermal expansion is as follows.

           $\alpha = \frac{1}{V}(\frac{\Delta V}{\Delta T})$

where,   V = initial volume

          $\Delta V$ = Final volume - initial volume

                      = (712.6 - 873.6) $cm^{3}$

                      = -161 $cm^{3}$

Now, we will calculate the change in temperature as follows.

          $\Delta T$ = Final temperature - Initial temperature

                       = (10 + 273) K - (70 + 273) K

                       = 283 K - 343 K

                       = -60 K

Substituting these values into the equation as follows.

     $\alpha = \frac{1}{873.6} \times (\frac{161}{60}) K^{-1}$

                 = 0.00307 $K^{-1}$

It is known that for non-ideal gases the value of alpha is 0.366% which is 0.00366 per Kelvin. As it is close to our result, hence the given sample of gas is a non-ideal gas.