Explain trends in the solubility of water (amount of the compound (solute) that will dissolve in a given amount of solvent (water).

The solubility of a compound in water refers to the maximum amount of that compound that can dissolve in a given amount of water at a specific temperature and pressure. The solubility of water varies greatly depending on the compound.

To understand the trends in the solubility of water, it's important to consider a few factors:

1. Polar and Non-Polar Compounds: Water is a polar solvent, meaning it has a positively charged region (hydrogen atoms) and a negatively charged region (oxygen atom). Polar compounds, such as salts and sugar, are generally soluble in water because they can form interactions with the water molecules through hydrogen bonding and electrostatic attractions. On the other hand, non-polar compounds, like oils, fats, and some hydrocarbons, are insoluble in water due to the lack of polar interactions.

2. Ionic Versus Covalent Compounds: Ionic compounds, such as NaCl (table salt) or KI (potassium iodide), tend to be highly soluble in water. These compounds dissociate into individual ions in water, which can be stabilized by the polar water molecules. On the contrary, covalent compounds, such as methane (CH4) or benzene (C6H6), are usually insoluble in water because their molecular structure does not allow for strong interactions with the polar molecules in water.

3. Temperature: The solubility of most solid solutes in water tends to increase with increasing temperature. This is because higher temperatures provide more kinetic energy to the water molecules, allowing them to "break" the bonds between the solute particles and further dissolve them. However, for some solutes, such as calcium sulfate (CaSO4), the solubility decreases with increasing temperature.

4. Pressure: Unlike gases, pressure doesn't significantly affect the solubility of solid or liquid solutes in water. However, pressure does have a profound effect on the solubility of gases in water. For example, the solubility of oxygen and carbon dioxide gases in water increases with increasing pressure.

In summary, the solubility of a compound in water depends on several factors, including the compound's polarity, ionic or covalent nature, temperature, and, for gases, pressure. Understanding these elements allows us to predict the solubility of various compounds in water. When specific compound solubilities are needed, it's best to consult solubility tables or databases, which provide precise values for different compounds at specific conditions.