chem exam

atomic radius

distance from the center of the nucleus to an electron on the valence shell

first ionization energy

the minimum amount of energy required to remove a mole or electrons from a mole of gaseous atoms to form a mole of gaseous ions

ionic radius

distance from the center of the nucleus to an electron on the valence shell of an ion

electronegativity

measure of the relative ability of atoms to attract a pair of electrons in a chemical bond (0-4 pauling scale)

electron affinity

energy given off or required when a mole of neutral atoms in the gaseous state gains a mole of electrons to form a mole of negatively charged ions in the gaseous state

accuracy

how close a measurement is to the true or accepted value

precision

how closely clustered a group of measurements of the same quantity are to each other

chemical bond

strong electric interactions of valence shell electrons between atoms that hold the atoms in close proximity to each other in molecules or crystals and occurs if an atom gains greater stability by bonding with another atom

dative bond

A covalent bond where one atom in the bond contributes both of the e- in the shared pair

ethyne

acetylene

ethene

vinyl, ethylene

propene (prop-1-ene)

propylene

methyl benzene

toluene

dimethyl benzene

xylene

1,2-dimethylbenzene

ortho-xylene

1,3-dimethylbenzene

meta-xylene

1,4-dimethylbenzene

para-xylene

hydroxybenzene

phenol

2-methyl-1,3,5trinitrobenzene

TNT, trinitrotoluene

homolytic fission

chemical bond dissociation of a neutral molecule generating 2 free radicals

heterolytic fission

one species keeps both electrons

general equation

CnH2n+2-2x-4y

oxidation number

The charge that an atom would have if all of the covalent bonds were broken and the more electronegative element kept all the electrons

Thermochemistry

the study of the energy changes that accompany physical, chemical or nuclear transformations of matter

System

the set of substances or reactants and products being studied (chemical equation)

Surroundings

all of the matter around the system that is capable of absorbing or releasing energy

open system

both energy and matter can move into or out of the system from/to its surroundings

closed system

energy can move into or out of the system but matter cannot

isolated system

ideal system where neither energy nor matter can move into or out of the system

temperature

the average kinetic energy of the particles in a sample of matter

activated complex

An unstable chemical species containing partially broken and partially formed bonds

activation energy

The minimum energy particles need for an effective collision

atom economy

• How much of your reactant goes into the actual product

• Higher atom economy = better for industry because there is less waste/byproduct

• Lower atom economy = less efficient

• Different to percent yield bc not looking at theoretical vs actual, looking at the nature of the reaction itself and seeing if it gives the intended product alot or a little

mole

standard counting unit for very large numbers

molar mass

mass of one mole of a substance

law of definite proportions

A given chemical compound always contains the same elements in the exact same proportions by mass

molecule vs formula unit vs atom

Molecule is made up of covalently bonded elements

Formula unit is the lowest ratio of ions in an ionic compound

Atom is the smallest unit of matter, molecules are made of atoms bonded together

percent composition

The percent by mass of each element in a compound

empirical vs molecular formula

Empirical formula: lowest whole number ratio of atoms in the compound

Molecular formula: true number of atoms in each molecule of the substance

isoelectronic

same amt of electrons