week 1 Flashcards
study of matter and the changes it undergoes
chemistry
the branch of chemistry that studies the properties and reactions of elements, excluding organic or certain carbon-containing compounds
inorganic chemistry
the branch of chemistry that deals with certain carbon-containing compounds
organic chemistry
the branch of chemistry dealing with compounds produced by living organisms
biochemistry
the study of those types of matter and changes in matter related to the disinfection, preservation and restoration of human remains
embalming chemistry
a measure of the amount of matter in a an object
- tendency to resist a change in motion
- not weight
- remains constant no matter where its placed
mass
anything that has mass and occupies space
-NOT mass
matter
the tendency of matter to become more disorganized or chaotic over time
-matter cannot be created or destroyed (laws of conservation of matter)
entropy
elements that make up the matter (water = hydrogren + oxygen_
composition
Substance- water
components- hydrogen, oxygen
atomic particles- protons, neutrons, electrons
subatomic particles
composition example of water
properties of matter (7)
- physical properties
- solubility
- chemical properties
- changes in matter
- physical changes post mortem
- chemical changes
- chemical changes post mortem
characteristics of a substance that are observed or measured without a change in chemical composition
- qualititative properties measure observed
- quantitative properties are measured
physical properties
physical qualitative properties (3)
- taste
- color
- odor
physical quantitative properties (4)
- melting point (solid to liquid)
- boiling point (liquid to gas)
-solubility
3 density (relationship between mass and volume occupied by that mass)
-mass per volume (g/ml or g/l) - specific gravity (density divided by the density of water
the relationship between mass and the volume occupied by that mass
-mass per volume (g/ml or g/l)
density
density divided by the density of water
specific gravity
the measure of how well a solute mixes with a solvent
-physical change
solubility
solubility (3)
- solvent
- solute
- solution
a substance that dissolves a solute in a solution
solvent
a substance dissolved in a solvent to form a solution
solute
a homogenous mixture of one or more solutes dissolved in a sufficient quantity of solvent
solution
characteristics of a substance observed during or after a chemical reaction
- can only be established by changing a substances chemical identity
- these properties can be used for building chemical classifications
- reactions are the result of observable chemical properties
chemical properties
result of observable chemical properties
chemical reactions
a change in the form or state of matter without any changes in chemical composition
- leads to a change in state
- water being heated to its boiling point and turning into steam
- frozen water melting
- sugar dissolving into water
physical change
physical changes post mortem (4)
- algor mortis
- livor mortis
- hypostasis
- dehydration
postmortem cooling of the body to the ambient temperature
algor mortis ; physical change
intravascular red-blue discoloration resulting from hypostasis of blood
livor mortis ; physical change
process of blood/fluids settling to dependent portions of the body due to gravity
hypostasis
the removal of water from a substance
dehydration
a change that results in the formation of a new chemical substance
- leads to the formation of a new substance
- rusting of iron
- burning of paper
- denaturing of an egg when it is fried
chemical change
chemical changes post mortem (5)
- cremation
- decomposition
- rigor mortis
- postmortem stain
- postmortem caloricity
the combustion, vaporization, and oxidation of human remains to basic chemical compounds
cremation
separation of compounds into simpler substances by the action of microbial and/or autolytic enzymes (initiated by hydrolysis)
decomposition
postmortem stiffening of the body muscles by natural processes (lack of atp)
-chemical change
rigor mortis
extravascular discoloration that occurs when heme seeps through the vessel walls and into the body tissues
-discoloration that results of hemolysis, chemical breakdown of erythrocytes (red blood cells)
postmortem stain
rise in body temp after death due to continued cellular metabolism
-ph shift from acid to base (protein breakdown)
postmortem caloricity
the process of chemical treating the dead human body to reduce the presence and growth of microorganisms, to temporarily inhibit organic decomposition, and to restore an acceptable physical appearance
- reduction in microbes by destroying the microbes themselves and limiting resources to them
- temporary preservation by injecting chemicals that prevent decomposition
- restoration with chemicals like humectants, dyes, surfactants and other supplemental chemicals
embalming
states of matter (3) plus subcategories (7)
- gases
- liquids
- (liquids) evaporation
- (liquids) condensation
- (liquids) dynamic equilibrium
- (liquids) vapor pressure
- (liquids) boiling
- solids
- (solids) melting
- (solids) sublimation
a state of matter that has no definite shape or volume
- least dense and most mobile
- particles moving at a high velocity
- high kinetic energy
- uniformly distributed throughout any container than defines them
- particles have no attraction for each other
- greatest amount of entropy
gases
key properties of gases (3)
- expansivity
- compressibility
- diffusibility
gas may increase volume when heated or placed into a larger container
expansivity
gas may decrease it volume when cooled or forced into a smaller container
compressibility
gases are able to move within and outside of a container
- gases exert pressure by colliding with the ways of what contains them
- more collisions, higher pressure
diffusibility
a state of matter having a definite volume but no definite shape
- particles touch one another which restricts movements
- do not respond dramatically to temp changes
- no definite shape
- fixed volume that conforms to the shape of the container
- soluble in one another but diffuse more slowly than gases
liquids
- liquid to gas
- rate of evaporation is correlated to the energy of the molecules in the liquid
- higher temp = higher kinetic energy
- not all the molecules at the same temp have the same energy; some on the surface can escape the attraction of neighboring molecules and transition into a vapor state
evaporation
gas to liquid
- occurs when some molecules in the vapor state return to the liquid state
- not observable in an open container
condensation
no net change in the liquid level
- still activity occurring
- eventually evaporation and condensation in a closed container will even out and reach ___
liquids ; dynamic equilibrium
the pressure exerted by gas molecules above a liquid
- depends on the attraction between molecules in a liquid
- more attraction = lower vapor pressure
(liquids) vapor pressure
liquid to vapor via heat
boiling
temperature at which the vapor pressure - atmosphere pressure or the temp at which a liquid changes to a vapor
- atmosphere is “pushed away” by the vapor formed
- liquids with a high boiling point have low vapor pressure
boiling point
heat or energy required to transform a given quantity of a substance from a liquid to a gas
heat vaporization
a state of matter having a definite shape and volume
- particles cling to each other rigidly
- shape independent of container
- repulsive forces between electrons prevent compression
- low vibrational movement but NOT motionless
solid
solid to liquid via heat
melting
temperature at which solids melt
-heat increases vibrational activity of particles until they begin to break free
melting point
quantity of energy required to turn a solid into a liquid
heat of fusion
solid to gas (directly)
-accompanied by an absortion of heat
sublimation
energy and matter (1)
- particle motion
- state of matter for any substance is determined by the amount of energy it possesses
- solids, liquids, and gases
particle motion
- heat is released when the physical state of matter changes from a gas to a liquid or from a liquid to a solid
- heat is absorbed when the physical state of matter changes from a solid directly to a gas or from a solid to a liquid or a liquid to a gas
- these reactions are classified as exothermic or endothermic
heat and energy
heat and energy (2)
- exothermic reactions
2. endothermic reactions
releases heat
- energy of activation is overcome by applying heat which releases stored and kinetic energy
- gasoline reacting with oxygen to produce energy in the form of heat in an engine
exothermic reaction
absorbs heat
-reactions aren’t as common, they go uphill energetically
endothermic reaction
from atoms to mixtures (4)
- mixture
- compound
- element
- atom
combination of two or more non chemically bound substances that can be made up of either elements or compounds
mixture
substance consisting of two or more elements combined chemically in definite proportions by mass
compound
simple substances which cannot be decomposed by ordinary chemical means
- pure substance
- 118 officially recognized
- 98 exist naturally
- oxygen is most abundant on earth
element
the smallest particle of an element that has all the properties of the element
- the final particle into which a chunk of matter can be divided and still retain its physical properties
- identity is determined exclusively by the number of protons and neutrons in its nucleus
atom
small, dense region at the center of an atom
-contains almost all the mass of an atom with a very small contribution from its orbiting electrons
nucleus
subatomic particles with a positive change
protons
subatomic particles with no net charge
neutrons
subatomic particles with a negative charge
- determine the chemical properties of an element
- unreacted atoms are neutral
- electrons are attracted to the protons of other atoms
electrons
atomic values (3)
- atomic # ; total # of protons
- atomic mass ; protons + neutrons
- # of electrons = number of protons
forms of an element with the same number of protons but different numbers of neutrons resulting in different atomic masses
-atoms of the same element always have the same atomic number but can have varying numbers of neutrons
isotopes
- electrons travel around the nucleus at defined distances
- distances are referred to ___
- lower the level number, lower the energy of the electron and closer it is to the nucleus
- each level holds a definite number of electrons
energy levels
- electrons must fill previous energy levels before moving on to the next level
- each energy level has sub levels
orbitals
the electrons available for chemical bond formation
- are those in the outermost layer of orbitals
- create a veil or mask over the underlying electrons
- determine the elements reactivity
valence electrons
PERODiC TABLE GROUPS
- vertical columns are considered
- main groups
- Alkali metal group
- Alkaline earth metal group
- Transition metals separate groups
- Halogen groups
- Noble gase group
- horizontal rows
- groups
- 1A-8A
- 1A
- 2A
- 2A and 3A
- 7A
- 8A
- periods
- each element closer to the right adds one more proton and one more electron
- chemicals in the same period have different valence electrons so they behave differently
- horizontal rows called
periods
- elements to the left of 3A are
- elements to the right of 3A are
- elements on the “staircase” are
- metals (except H)
- nonmetals
- metalloids
valence electrons determine how an atom will bond
- elements form bonds with each other to achieve a full complement of valence electrons
- nature of the bond is related to the distance between the atoms
chemical bonding
atoms favor having 8 valence electrons
octet rule
a chemical bond formed between 2 atoms by the sharing of electrons
- usually occurs between similar atoms
- “perfect” covalent bond is between diatomic molecules (2 of the same)
- tends to be more stable
- name literally means sharing valences (electrons available for chemical bond formation)
covalent bonds
-occurs when atoms share more than one pair of electrons
double and triple bonds
chemical bond formed oppositely charged atoms
- atoms lose or gain electrons
- no longer a balance between the positive charge on the nucleus and the negative charge of the electrons
ionic bonds
an atom or group of atoms with a positive or negative electrical charge
ion
atoms that gain an electron (anion)
negative ions
atoms that lose an electron (cation)
positive ions
bonds that combine partial ionic character with partial covalent character
- based on electronegativity
- entire molecule remains neutral
- usually form between unlike atoms
polar covalent bonds
bond combining two identical or similarly electronegative atoms (even distribution of electrons)
non polar covalent bonds
the ability to attract valence electron density
- when atoms are drawn more closely to one of the atoms in a covalent bone, the bond is polarized
- atoms in the upper right hand of the periodic table are the most electronegative, bottom left hand corner is the least electronegative
electronegativity
reactants -> products
- laws of conservation
- balancing coefficients
reactions
the numbers in front of the chemical formulas
-multiply each part of the symbol or formula
balancing coefficients
two or more elements (or compounds) combine to form a single product
- A+B=AB
synthesis (combination) reactions
breakdown of a reactant into 2 or more constituent parts
- AB -> A+B
decomposition reactions
one element (usually a metal) replaces another metal or hydrogen from a compound A + BC-> AC+B
single replacement reactions
two reactants and 2 products all of which are compounds that “change partners” to form products
AB+CD->AD+CB
double replacement (metathesis)
