Chapter 11 - Chemical Evidence Flashcards
Analytical Chemisty
Branch of chemisty that deals with the seperation, purification, identification, quantification of substances
Anion
A negitivley charged ion
Atom
The smallest particle of an element that can exist and still retain its identity as an element.
Atomic Mass
Weight
- Mass of an atom that’s expressed in the standard unit of atomic mass units (amu)
- Equal to the # of protons and neutrons in the atom
AMU
Unit of mass that weighs 1/12th the mass of a carbon atom containing 6 protons and 6 neutrons
atomic mass unit
Atomic number
The # of protons in the nucleus of an atom
Cation
A positivley charged ion
Chemical analysis
The study of the chemical composition and structure of substances
Chemical Equation
Repsentation of a reaction showing the reactants combined to form the products
Chemical Property
Characteristic of a substance that can be observed in a chemical reaction
Chromatography
Process for separating components of a mixture
Concentration
- Amount of solute dissolved in a quantity of solvent
- Given in moles of solute in 1 liter of solution (molarity)
Law of Conservation of Mass
Matter cannont be created or destroyed during a chemical reaction
Density
The mass of a substance per unit volume
Detection Limit
The smallest amount of substance that can determine the composition of a substance
Electron
- Small, stable particles
- Are negatively charged
- Equal and opposite to the + charge on protons
Element
Substance that cannot be broken down into smaller parts/changed into another substance
Empirical Formula
Chemical formula of a compound that gives the proportions (ratios) of the elements present
Heterogenous Mixture
- Composed of 2 or more substances
- Visually distinct components
Homogenous Mixture
- Composed of 2 or more substances
- Appears uniform throughout
Indicator
Monitors changes of properties (color, conductivity) in a reaction
Instrumental Analysis
Deals with using complex, specific instruments to measure/ analyze the physical properties of samples
Interference
Substance that obstructs/interferes with the chemical analysis of another substance in a mixture
Ion
A charged particle or molecule
Isomers
Different compounds with the same molecular formula
Isotope
Members of a family of an element that all have the same # of protons but different #s of neutrons
Liquid
Substance that has no definite shape but a fixed volume
Molecular Formula
Gives the total # of atoms of each element present in a molecule
Molecular Weight
- Mass of a molecule that is expressed in AMU
- Sum of the individual weights of atoms that make up the molecule
Neutron
- Particle with no charge
- Has the same mass as a proton
Reactant
- Substance that reacts during a reaction
- Eventually changed into a different substance
Periodic Table
- Table of the known chemical elements
- Arranged by increasing atomic #s
- Elements with similar chemical properties are arranged in vertical rows
Physical Properties
- Property used to characterize a substance without a chemical reaction
- Boiling point, density
Product
Substance that is the result of the reactants (reaction)
Proton
- Particle with about the same mass as a neutron
- Has a positive electrical charge equal and opposite to an electron
Quantitative Analysis
Measurement of the amounts of the components in a substance
Qualitative Analysis
Determination of the identities of the components in a substance
Retention Factor (Rf)
Rf value is the ratio of the distance traveled by the substance to the distance traveled by the solvent front
Solid
Substance that has a definite shape and fixed volume
Solubility
Degree to which a solute (solid) will dissolve in a solvent
Solute
Substance dissolved in a solvent
Solvent
The liquid that is used to dissolve a solute
