contains the interaction of a cation with the solvent. In the figure for Exercise 13.1, we see a
cation separated from the bulk sample, and solvent molecules
interacting with each other as well as the cation. The diagram shows attractive solvent-solvent
and ion-solvent interactions, which contribute to an overall negative (–)
H. In Figure 13.4, only
The pink solid is hydrated
where x is a specific integer. The waters of
hydration are either associated with Co
, or sit in specific sites in the crystal lattice. When
heated in an oven, the water molecules incorporated into the crystal lattice gradually gain kinetic
energy and vaporize. The blue solid is anhydrous CoCl
, absent the waters of hydration and with
a different solid-state structure than the pink hydrate.
Diagram (b) is the best representation of a saturated solution. There is some undissolved solid
with particles that are close together and ordered, in contact with a
solution containing mobile, separated solute particles. As much solute has dissolved as can
dissolve, leaving some undissolved solid in contact with the saturated solution.
Solubility increases in the order Ar, 1.50
< Kr, 2.79
< Xe, 5
order of increasing polarizability. As the molar mass of the ideal gas increases, atomic size
increases and the electron cloud is less tightly held by the nucleus, causing the cloud to be more
polarizable. The greater the polarizability, the stronger the dispersion forces between the gas
atoms and water, the more likely the gas atom is to stay dissolved rather than escape the
solution, the greater the solubility of the gas.
changes with a change in temperature. Molarity is defined as moles
solute per unit volume of solution. If solution volume is different, molarity is different.
does not change with change in temperature. Molality is defined as moles
solute per kilogram of solvent. Even though the volume of solution has changed due to
increased kinetic energy, the mass of solute and solvent have not changed, and the
molality stays the same.