Mixtures and Solutions
* A mixture maintains its identity regardless of the proportions of its components. * A mixture can be separated into its pure components through physical separation techniques. * The components are distributed uniformly throughout a homogenous mixture. * The components are not distributed uniformly throughout a heterogeneous mixture. * A solution is composed of a solvent and one or more solutes. The solvent is present in the greater amount. In an aqueous solution, water is the solvent. * Polar solvents tend to dissolve polar solutes, and nonpolar solvents tend to dissolve nonpolar solutes. * When a molecule dissolves in solution, the chemical bonds of the molecule remain intact. * When an ionic compound dissolves in solution, the lattice dissolves and the ions are surrounded by water molecules. * An electrolyte is an ion dissolved in water.
* Concentration is expressed as a ratio: The amount of solute is the numerator and the total amount of solution is the denominator. * The most commonly encountered units of concentration in the medical field are mass/volume, %mass/volume, moles/volume, and equivalents/volume.
Colloids and Suspensions
* Colloids contain particles that are much larger than typical solute particles. * Suspensions are mixtures in which particles are unevenly distributed throughout the medium, and eventually settle.
Membranes, Osmosis, and Dialysis
* Substances can move across a semipermeable membrane through osmosis and dialysis. * Osmosis and dialysis regulate the distribution of nutrients in the cell and the removal of waste products from the cell. * Simple diffusion is the spontaneous movement of a molecule or ion from a region of higher concentration to a region of lower concentration. * In osmosis, water crosses a semipermeable membrane by simple diffusion from a region of lower solute concentration to a region of higher solute concentration. * In dialysis, solutes cross a semipermeable membrane by simple diffusion from a region of higher solute concentration to a region of lower solute concentration. * The relative concentrations of solutions on either side of a semipermeable membrane can be described as hypertonic (having the higher concentration), hypotonic (having the lower concentration), or isotonic (having the same concentration). * Colloidal particles cannot cross a semipermeable membrane; therefore, dialysis is a technique used to separate solutes from colloidal particles.
Chapter 6: Hydrocarbons and Structure
* Organic compounds are compounds containing one or more carbon atoms. * Hydrocarbons are organic compounds composed of only carbon and hydrogen atoms. * There are four types of hydrocarbons: alkanes, alkenes, alkynes, and aromatic hydrocarbons. * Alkanes are saturated hydrocarbons.
* Alkenes, alkynes, and aromatic hydrocarbons are unsaturated hydrocarbons. * Hydrocarbons are nonpolar and hydrophobic substances, and therefore insoluble in water. Hydrocarbons are hydrophobic – water fearing.
Saturated Hydrocarbons: The Alkanes
* Alkanes are saturated hydrocarbons containing no multiple bonds: only carbon-carbon single bonds and C-H bonds. * Alkanes have a tetrahedral geometry around each of their carbon atoms, giving a chain of three or more carbon atoms a zigzag appearance. Bond angles are 109.5degrees. * Conformations are rotational forms of the same compound. Alkanes can rotate freely around their carbon-carbon single bonds and therefor give rise to many different conformations. * Structural isomers have the same chemical formula but a different connectivity of atoms. They are different compounds so they have different physical and chemical properties.
* Condensed structural formulas simplify the process of...