Q12.135P - Chemistry: Molecular Nature Of Matter And Change

Question

The density of solid gallium at its melting point is  $\mathbf{5}\mathbf{.}\mathbf{9}\mathbf{g}\mathbf{/}{\mathbf{cm}}^3$, whereas that of liquid gallium is  $\mathbf{6}\mathbf{.}\mathbf{1}\mathbf{g}\mathbf{/}{\mathbf{cm}}^{\mathbf{3}}$. Is the temperature at the triple point higher or lower than the normal melting point? Is the slope of the solid-liquid line for gallium positive or negative?

Step-by-Step Solution

Answer

The density of the liquid having $6.1 {\mathrm{gcm}}^{-3}$  is higher than that of the solid having density $5.9 \mathrm{g}/{\mathrm{cm}}^3$ because as the pressure increases, the solid gets converted into a liquid state.

Definition

The density of the molecule can be defined as the ratio of the mass of the molecule to the volume occupied by the molecule.

 

$\mathbf{Density}\mathbf{=}\frac{\mathbf{Mass}}{\mathbf{Volume}}$ 

The phase diagram is the diagram showing the change in the phase of the molecule do the change in the temperature and pressure shown in the two-dimensional temperature at one axis and pressure at other axes.

Numerical Explanation

The density of solid Gallium  $=5.9 \mathrm{g}/{\mathrm{cm}}^3$

The density of the liquid Gallium  $6.1 \mathrm{g}/{\mathrm{cm}}^3$

The density of liquid gallium is greater than the density of solid gallium, as explained in the below phase diagram.

According to the phase diagram, there is a negative slope of solid liquid, and as one increases the pressure, the solid gallium is converted into liquid gallium.