November 7, 2013
Fire is a self-sustaining chemical reaction that releases heat energy and light. It involves
oxidation and combustion.
Arson investigators seek to determine whether a fire was deliberately set to destroy
The fire t
September 10, 2013
How much matter takes up a certain amount of volume.
Density units: mL
Mass units: g
Volume units: cm3=cc
big/small= high density
small/big= low density
Ice floats in Water: ice is less dense than water, so it floats
September 5, 2013
CH.2: Evidence Collection and Preservation
If evidence is not preserved properly, it can be damaged through chemical changes it overgoes
over time-must preserve its original state
chemical changes: matter undergoing chemical reaction
September 3, 2013
Chemists study matter at the molecular level; the reaction between matter
organized based on atomic #/atomic mass
columns=family-> they react; similar physical properties; Group
rows= period (neighbours); each element act
Chapter 4: Chemical Evidence
The Purpose of the Periodic Table:
1. predict the pattern of properties (both physical and chemical)
2. predict the molecular formula
All metals give electrons-when you mix metals with non-metals, the non-metals will
September 26, 2013
Chemical reactions are very important to forensic scientists and to officers in the field
Field tests for commonly controlled substances allow officers to collect important
evidence and disregard househol
October 1, 2013
Types of Reactions:
Metathesis (double displacement)
A segment of each compound in the reaction is exchanged with the other reactant, leading to the
formation of 2 new compounds.
Precipitation Reactions: the formation of a solid
October 3, 2013
All molecules in a particular compound have a unique three-dimensional shape
Understanding the three-dimensional shapes of molecules is vitally important in understanding
how drug molecules function in our body.
The nature of th
September 12, 2013
electron, neutron, proton in an atom
JJ Thomson-> measured the charge to mass ratio; 1850s electrons discovered as cathode rays in
a cathode ray tube a sealed glass tube from which nearly all gases have been removed, cr
October 8, 2013
Polarity of Bonds and Molecules
The physical and chemical properties of any molecule are strongly affected by whether it is polar
or not (which solvents it will dissolve in, the melting and boiling points, how one molecule will
November 5, 2013
How to extract Organic Compounds: solubility and acid-base properties
Arrhenius definition: acids are compounds that produce free H+ ions in an aqueous solution;
bases are compounds that produce free OH-ions in an aqueous solut
What qualities make a compound to be explosive?
Ability to rapidly release a large amount of energy.
But coal produces more energy per gram than nitroglycerin does.
So we see that the speed of reaction is what makes a compound exp
October 29/31, 2013
Organic Compound: composed primarily of carbon and hydrogen atoms
inorganic compound: composed of elements from the rest of periodic table
*The name of the compound provides info. about the number of car
October 17, 2013
Chapter 7: Properties of Solutions II: Intermolecular Forces and Colligative Properties
Intermolecular Forces: attractive forces that develop between adjacent particles
not as strong as covalent or ionic bonds that exist within particles
October 15, 2013
Concentration (pg 174):
The concentration of a solution tells us how much solute we have in a given volume of solution
or solvent. (the higher the moles, the higher the concentration)
It can be expressed in terms of grams per 1
A poison can be defined as a substance that injures living things.
Such substances (elements or compounds) cause illness or death even when ingested or
absorbed in small quantities, often by interfering with normal cell functions.
October 22, 2013
Dissolution: the interaction of water molecules with a solute such that the solute molecules or
ions are pulled away from each other and dispersed throughout the water.
The negative region of water will be attracted to any substance with
Chemical kinetics is concerned with the speeds or rates of chemical reactions and the
mechanisms by which they occur.
Like other chemical and biochemical processes, the speed of insect growth is very
October 10, 2013
A solution consists of a solvent, the dissolving medium, and the solute, the material (s, l,
or g) being dissolved.
If both solute and solvent are liquids, the solute is the one present in smaller amount.