the chemical level of organization

• chemistry is the science of structure and interactions of matter • matter is anything that has a mass and takes up space • mass is the amount of matter a substance contains, whereas weight is the force of gravity acting on mass

matter exists in 3 forms: solid liquid gas all forms of matter and composed of chemical elements

elements are given chemical symbols such as : o=oxygen c=carbon h=hydrogen n=nitrogen these elements make up the majority of our bodies

oxygen ; o carbon ; c hydrogen ; h nitrogen ; n the percentage is about 96% of total

calcium ; ca phosphorus ; p potassium ; k sulfur ; s sodium ; na chlorine ; cl magnesium ; mg iron ; fe the percentage is about 3.6% of total

the percentage is about 0.4% of total

chemical elements are composed of units of matter of the same type called atoms atoms are the smallest units of matter that retain the properties and characteristics of an element

atomic number is the number of protons in the nucleus of an atom mass number is the number of protons and neutrons in an atom

atomic mass assumes the mass of the neutron, proton, and electron the atomic mass\weight of an element is the average mass of all its naturally occurring isotopes

ion is an atom that has lost or gained an electron molecule as 2 or more atoms sharing electrons compounds is a substance that can be broken down into 2 or more different elements

a chemical bond occurs when the atoms are held together by forces of attraction the number of electrons in the valence shell determines the likelihood that an atom will form a chemical bond with another atom

a positive charge ion when you give an electron

is a negative charge ion when you receive an electron

can be single, double, and triple bonds

hydrogen bonds result from the attraction of the oppositely charged parts of molecules

hydrogen bonds between water and molecules give water cohesion cohesion is the tendency of like particles to stay together hydrogen bonds create surface tension surface tension is a measure of the difficulty of stretching or breaking the surface of a liquid

chemical reactions occur when new bonds are formed or old bonds are broken reactants are the starting substances products are the ending substances metabolism

energy is the capacity to do work potential energy kinetic energy chemical energy law of the conservation of energy- energy can neither be created nor destroyed but it can be converted from one form to another

exergonic reactions endergonic reactions activation energy

synthesis decomposition exchange reversible oxidation-ruduction

these reactions transfer electrons between atoms and molecules and always occur in parallel(when one substance is oxidized is reduced) oxidation is a loss of electrons and energy release reduction is the gain of an electrons and energy gain

inorganic compounds usually lack carbon and are simple molecules water is the most important and abundant inorganic compound in all living things organic compounds always contain C, usually contain O, and always have covalent bonds

water is the ideal medium in a hydrolysis reaction, water is added to break bonds in a dehydration synthesis reaction, water is removed to make bonds

water has a high heat capacity and a high heat of vaporization