States of Matter

Uric acid is the least toxic and least soluble nitrogenous waste, which allows animals like birds and reptiles to conserve water by excreting it as a semi-solid paste.

Ammonia is highly soluble in water, which is why aquatic animals can easily excrete it into their surrounding water.

Water equivalent is the mass of water that would require the same amount of heat as the body to raise its temperature by one degree, thus it is measured in units of mass (grams).

Covalent compounds are generally non-polar or weakly polar, making them more soluble in organic solvents (like benzene or ether) than in water, which is a highly polar solvent.

Ionic compounds are polar in nature and dissolve readily in polar solvents like water due to the hydration energy overcoming the lattice energy. They are generally insoluble in non-polar solvents like ether or benzene.

Pure water is a chemical compound consisting of H2O molecules, whereas air and sea water are mixtures of various substances. A mixture contains two or more substances physically combined, while a compound is a pure substance.

Evaporation is a surface phenomenon that occurs at any temperature below the boiling point of a liquid. Boiling, in contrast, occurs only at a specific temperature.

Freezing is an exothermic process. To transition from a liquid to a solid, the substance must release energy to the surroundings.

The melting point is the specific temperature at which a solid substance begins to transition into a liquid state at a given pressure.

During phase changes like melting, freezing, and boiling, the temperature of a substance remains constant because the energy supplied is used to overcome intermolecular forces rather than increasing kinetic energy.

Naphthalene, iodine, and camphor are substances that undergo sublimation. Butter does not sublime; it melts into a liquid before it can be vaporized.

Dry ice (solid CO2) undergoes sublimation, transitioning directly from a solid to a gas at atmospheric pressure.

Evaporation is an endothermic process that absorbs heat from the surroundings, causing a cooling effect. This principle is the basis for how refrigeration systems work.

Fractional crystallization is a method used to separate substances from a mixture based on differences in their solubility at different temperatures.

The energy required to convert a unit mass of a liquid into a vapor at its boiling point is called the latent heat of vaporization.