Chapter 1- Intro to Forensic Chemistry Flashcards
Matter
physical material of the universe; has three states; solid, liquid, gas
Solid
particles are in close proximity to each other and are held by attractive forces. Particles in solids are tightly compressed + heat to make liquid, becomes solid from liquid by - heat
Liquid
particles are farther apart than solid, allowing liquid to flow freely, cannot be easily compressed. Volume is consistent and liquid takes the shape of the container holding it
Gas
large distances between particles, they move at high speeds and can be compressed. Gas will always fill volume and shape of container.
Pure Substance
form of matter with a uniform composition which cannot be separated by physical methods.
Elements
Simplest form of a substance; smallest part=atom
Compounds
made up of atoms from 2 or more elements, chemically bonded together; two types, molecular and ionic
molecular compounds
molecule=the simplest compound unit
ionic compounds
formula unit=simplest unit
Mixtures
2 or more pure substances that are physically combined; two kinds, homo and hetero-geneous
Homogeneous
one of the substances are so evenly distributed that any single part of the substance will match all others; very well mixed; ex: sugar and water
Heterogeneous
composition varies; does not mix well; ex: soil, trash, oil and water
Atomic symbols
formed from first (or second or third) letter of name of element, some symbols come from Latin names of elements
Metals
metals share the properties: good conductors of energy and heat, solid at room temp, form metallic bonds with each other in which electrons are free to move from one atom to another (conduction)
Non-metals
do not conduct electricity or heat very well and can be found as a solid, liquid, or gas. They have melting points much lower than metals.
