Cliff's - Chapter 1- Chemistry Flashcards
Atom
- postively charged protons
- neutrall charged nuetrons
- negatively charged electrons oriented around nucleus
molecules
two or more atoms conneced by bonds
chemical bonds formed via
interaction between their electrons of atoms
electronegativity
ability of an atom to attract electrons
chemical bonds
(types)
- ionic
- covalent
- polar covalent
- nonpolar covalent
- hydrogen
ionic bonds
electrons are transferred from one atom to another
electronegativities of atoms are very different
more en atom pulls electron
atom that gains electron: negatively charged
atom that loses electron: positively charged
charges –> ions
ionic bond = attraction bw positve and negative charge ions
e.g. NaCl
Covalent Bond
electrons between atoms are shared
electronegativities of atoms are similar
polar covalent
nonpolar covalent
nonpolar covalent bond
electrons shared equally
two atoms sharing electrons are identical - en are identical
e.g. O2
polar covalent bonds
electrons shared unequally
atoms have different electronegativities
electrons forming bond closer to atom with greater en
negative charge (pole) on more en atom
postiive pole on less en atom
e.g. h2o
single, double, triple covalent bonds
2, 4, 6 electrons are shared, respectively
hydrogen bonds
weak bonds bw molecules
positively charged hydrogen atom in one covalently bonded molecule attracted to a negatively charged atom (O, N or S) in another covalently bonded molecule
Properties of Water
(due to H bonding b/w water molecules)
- water is excellent solvent
- water has high heat capacity
- ice floats
- water has strong cohesion and high surface tension
- water has strong adhesion
Water is an excellent solvent
ionic substances soluble in water - poles of polar water mlc interact with and separate ionic substances into ions
polar covalent substances also soluble - interactions of poles with water
nonpolar covalent substances do not dissolve in water - no charged poles
hydrophilic
substances that dissolve in water
“water-loving”
hydrophobic
substances that do not dissolve in water
“water fearing”
heat capacity
degree to which substances change temperature in response to gain or loss of heat
water has high heat capacity
water changes temp very slowly with changes in heat content
temp of large bodies of water very stable in response to air
a lot of energy need be added/removed to heat/cool water
ice floats
most substances contract and become more dense when frozen
water expands and becomes less dense when frozen
thus - floats in liquid water
solid state of water - h bonds rigid and form crystal, keeping mlc separated
water has strong cohesion and high surface tension
cohesion - attraction bw like substances - because of h bonding
cohesion produces high surface tension
water has strong adhesion
adhesion - attraction of unlike substances
when water adheres, demonstrates capillary action:
rises up tubing or creeps through papers
Organic Molecules
have carbon atoms
macromolecules
large organic molecules
polymers
molecules consisting of a single monomer repeated many times
functional groups
in organic molecules
each gives molecule particular property
hydroxyl
(functional group)
-OH
alcohols
polar
hydrophilic
carboxyl
(functional group)
carboxylic acids
polar
hydrophilic
weak acid
amino
amines
polar hydrophilic
weak base
phosphate
organic phosphates
polar
hydrophilic
acid
e.g. DNA, ATP, phospholipids
carbonyl
(functional group)
ketones, aldehydes
polar
hydrophilic
methyl
(functional group)
nonpolar
hydrophobic
Four classes of organic molecules
carbohydrates
lipids
proteins
nucleic acids
Carbohydrates
classified into 3 groups based on number of sugar (saccharide) molecules present
- monosaccharide
- disaccharide
- polysaccharide
monosaccharide
simplest carbohydrate
single sugar molecule
e.g. fructose, glucose
sugar molecule formula
(CH2O)n
n = 3,4,5,6,7,8
disaccharide
two sugar molecules joined by glycosidic linkage
in joining, water molecule lost
(formula = -H2O)
condensation reaction
chem rxn where simple molecule is lost
dehydration reaction
chem rxn where water molecule is lost
common disaccharides
sucrose = glucose + fructose (table sugar)
lactose = glucose + galactose (sugar in milk)
maltose = glucose + glucose
glycosidic linkage
covalent bond
joins hemiacetal group of saccharide to hydroxyl group of another organic compound
polysaccharide
series of connected monosaccharides
polymer (repeating units of a monosaccharide)
e.g.: starch, glycogen, cellulose, chitin
starch
polymer of alpha-glucose molecules
principle energy storage molecule in plants
glycogen
polymer of alpha-glucose molecules
differs from starch by pattern of polymer branching
major energy storage molecule in animals
cellulose
polymer of beta-glucose molecules
structural molecule in walls of plant cells
major component of wood