Chapter 2- chemistry of life

stephanieyw's version from 2018-10-04 01:18


Question Answer
elements and atomsmore than 100 elements identified- over 30 important to living things- 90% of mass is made up of oxygen, hydrogen, carbon, and nitrogen
Periodic tablesymbols have 123 letters --- atomic number is # of protons----atomic mass is =to tota; # of P & N
atomnucleus- central region of atom + contains pro and N----- electrons move around nucleus------net electrical charge of atom is 0
orbitals specific energy level----each level can only hold a certain # of electrons-------1st level = 2 electrons has 1 orbital------8 electrons has 2 orbitals-------max of 2 electrons in each orbital
Isotopesatoms of same element with different number of neutrons------changes mass of element
compounds + chemical bonds2 or more elements--chemical formula-----------chemical bonds= attractive force that holds atoms together*Covalent*ionic*hydrogen
covalent bonds2 atoms chare 1/more pairs of electrons--------molecule= simplect part of a substance that retains all of the properties of that substance and can exist in a free state
ionic bondspositive and negative electrical charges attract each other
Energyability to do work
states of mattersolid= closely linked- move less rapidly- fixed volume and shape Liquid= fixed volume + conform its shape Gas= most rapidly+fill the volume of a container Thermal energy must be added to change state
energy and chemical reactionsduring reaction E is absorbed/ released when bonds are broken and formed
reaction directionreactants--> products 2 way bidirectional equation
Catalysts and EnzymesCatalyst reduce amount of activation energy needed for a reaction to take place enzymes= catalysts in living things & speeds up metabolic reactions
oxidation Reduction reactionstransfer of electrons--redox reaction---oxidation: loses one/ more electrons --> (=) charge Reduction: gain one/more electrons--> (-) charge redox always occur together
Properties of Water:)
Properties of water 2solubility- disolves polar substances: sugar, ionic commpounds, some proteins-------cant dissolve non polar substances: (oil) bc weak attraction H2) attracted to each other-----hydrogen bonds--cohesion and adhesion
temp and moderationabsorbed or release energy--> heat with slight change in temp* specific hear Density of ice-- solid water is less dense than liquid water bc shape of h20 molecule and hydrogen bonding ------------------bodies of water: freeze from the top down----insulates the water below for the cold air = life
solutionsmizture in which one or more substances are uniformly distributed in another substance----------mixtures of liquid, solids, and gases------------------------solute and solvents :::::: solutes dissolve in solvents------aqueous solution: water is the solvent
Acids and basesOH- = hyroxide ions:::::::: H30+ = hydronium ions
acidsmore H30+ in a solution----sour taste; acidity------ highly corrosive to some materials
bases more OH---- akaline-- bitter taste---- feel slippery: OH- reacts w/ oil on skil--soap========== commercial soaps are made up of a base and a fat
buffersneutralize small amounts of either an acid or a base added to a solution----control pH in a system