Solubility is

• the maximum amount of solute that dissolves in a specific amount of solvent

• temperature sensitive for solutes

• expressed as grams of solute in 100 grams of solvent, usually water

Saturated solutions

• contain the maximum amount of solute that can dissolve • have undissolved solute at the bottom of the container

• contain solute that dissolves as well as solute that recrystallizes in an equilibrium process 

Unsaturated solutions

• contain less than the maximum amount of solute

• can dissolve more solute

An isotonic solution

• exerts the same osmotic pressure as body fluids such as red blood cells (RBCs)

• of 5.0% (m/v) glucose or 0.90% (m/v) NaCl is a typical isotonic solution

A hypotonic solution

• has a lower solute concentration than RBCs

• means water flows into cells by osmosis 

A hypertonic solution

• has a higher solute concentration than RBCs

• causes crenation: RBCs shrink in size In a hypertonic solution, water goes out of the cells by osmosis.

Mass percent (% m/m) is the

• concentration by mass of solute in a solution

• grams of solute in 100 g of solution (conversion factor for mass percent)

mass percent m/m=g solute/g of solute+ g solvent x100

mass percent=g of solute/100 g of solution

Molarity (moles of solute/liter of solution) is defined as the moles of solute per volume (L) of solution.

M=moles of solute/liters of solution

Solutions

• are transparent

• do not separate

• contain small particles, ions, or molecules that cannot be filtered and pass through semipermeable membranes

Colloids

• have medium-size particles

• cannot be filtered

• can be separated by semipermeable membranes

Suspensions

• are heterogeneous, nonuniform mixtures

• have very large particles that settle out of solution • can be filtered

• must be stirred to stay suspended

Examples include blood platelets, muddy water, and calamine lotion.

• Solutes dissolved in water effect the freezing point and boiling points. These are called colligative properties.

• Depends only on the number of solute particles in the solution

• Solutes disrupt the formation of water crystals and reduce the vapor pressure of water – causing a higher boiling point

• Examples are salt on icy roads to lower the freezing point of the ice and antifreeze in cars to lower the freezing point of the water in your radiator. Antifreeze also raises the boiling point of the mixture so it doesn’t boil over in hot weather.

An isotope of an element that emits radiation is called a radioisotope.

When radiation is emitted, a radioisotope

• may undergo a change in the number of protons

• may be converted to an atom of another element

In nuclear fission, a large nucleus

• is bombarded with a small particle

• splits into smaller nuclei and several neutrons, releasing large amounts of energy called atomic energy

When a neutron bombards 235U,

• an unstable nucleus of 236U undergoes fission (splits)

• smaller nuclei such as Kr-91 and Ba-142 are produced

• the neutrons emitted have high energy and bombard more U-235 nuclei

Fusion reactions

• occur at extremely high temperatures (100 000 000 C) • combine small nuclei into larger nuclei

• release large amounts of energy

• occur continuously in the sun and stars, producing large amounts of energy

An alpha () particle has two protons and two neutrons, and it is identical to He nucleus (2+ charge is omitted).

A beta () particle is a high-energy electron, with a charge of −1, formed when a neutron is changed to a proton.

Gamma rays (γ) are the high-energy radiation released from a nucleus when it decays. They have no mass or charge.  

Radiation protection requires

• paper and clothing for alpha particles • a lab coat or gloves for beta particles

• a lead shield or a thick concrete wall for gamma rays

• limiting the amount of time spent near a radioactive source

• increasing distance from the source

• curie (Ci), the number of disintegrations that occurs in 1 s for 1 g of radium, equal to 3.7 × 1010 disintegrations/s

• rad (radiation absorbed dose), which measures the amount of radiation absorbed by a gram of material such as body The rem (radiation equivalent in humans) measures biological effects of different types of radiation, including

• alpha particles, which do not penetrate the skin; however, if they enter the body, extensive damage may occur in tissues

• high-energy radiation, such as beta particles, high-energy protons, and neutrons, which travels into tissues and causes more damage than alpha particles

• gamma rays, which are damaging because they travel a long way through body tissue

LD50

• is the amount of radiation to the whole body that is the lethal dose for one-half the population

• varies for different life forms, as Table 5.6 shows Whole-body radiation of 600 rem or greater would be fatal to all humans within a few weeks.

Alkanes

• are hydrocarbons that contain only C—C and C—H bonds • are formed by a continuous chain of carbon atoms • are named using the IUPAC (International Union of Pure and Applied Chemistry) system

• have names that end in ane • use Greek prefixes to name carbon chains with five or more carbon atoms

Alkyl groups are

• groups of carbon atoms attached to carbon chains

• named in the IUPAC system with an yl ending

Alkenes and alkynes are families of hydrocarbons that

• contain double and triple bonds, respectively

• are called unsaturated hydrocarbons because they do not contain the maximum number of hydrogen atoms

• react with hydrogen gas to increase the number of hydrogen atoms and become alkanes

Alkenes contain one or more carbon– carbon double bonds. In ethene, C2H4 , two carbon atoms are connected by a double bond. Each carbon atom in the double bond is attached to two hydrogen atoms and has a trigonal planar arrangement with bond angles of 120°.

Alkenes and alkynes are families of hydrocarbons that

• contain double and triple bonds, respectively

• are called unsaturated hydrocarbons because they do not contain the maximum number of hydrogen atoms

• react with hydrogen gas to increase the number of hydrogen atoms and become alkanes

Alkynes contain one or more carbon–carbon triple bonds. In ethyne, C2H2 ,

• two carbon atoms are connected by a triple bond

• each carbon is also bonded to one H atom Each carbon atom in the triple bond has a linear arrangement with bond angles of 180°

Benzene is

• an aromatic compound

• a ring of six C atoms, each bonded to one H atom

• a flat ring structure drawn with three alternating double bonds

• represented by two structures because the electrons are shared equally among all the C atoms

• represented by a skeletal formula using a circle in the center instead of the alternating double bonds