ACS Gen Chem 1 Exam

Ion

A species of an element in which the number of electrons does not equal the number of protons.

Isotope

Each isotope of an atom has a different number of neutrons.

Isoelectric

Two atoms with the same charge.

Isotopic

Two atoms with the same number of neutrons.

Transition Metal Orbitals

The 4s orbital is filled before the 3d orbital, but listed after.

Paramagnetic

Atoms that possess a permanent magnetic charge due to the presence of unpaired electrons.

Electropositive

Tending to lose electrons and form positive ions.

Tetrahedral Bond Angle

109.5°

Resonance Structures

Two equally correct arrangements of one molecule's electrons; generally the molecule exists as an average of the two.

Polar Molecule

A molecule that is mostly positive on one side and mostly negative on the other.

sp³ Orbital

An orbital composed of one s orbital and three p orbitals; can hold eight total electrons. Tetrahedral.

Trigonal Planar

The way that three objects will arrange themselves around a central atom. Non-polar.

Free Radicals

Compounds with an odd number of electrons in their Lewis Structure. Eg. NO₂

Incomplete Octets

Occur in elements that can form stable bonds with less than eight electrons. Eg. BF₃

Expanded Octets

Occur in the third row of the periodic table and beyond in elements that can form stable bonds with more than eight electrons. Eg. XeF₂

Hydrogen Bonding

When hydrogen is attracted to electronegative atoms.

Sigma Bonding

Formed by head-on overlapping between orbitals.

Coordinate Covalent Bonding

A covalent bond in which the two electrons derive from the same atom; occurs most often between Lewis acids and bases.

Hybridization

Mathematical procedure in which the standard atomic orbitals combine to form new orbitals.

sp² Orbital

Composed of one s orbital and two p orbitals; can hold six total electrons. Trigonal planar.

Pi Bonding

Bonding occurs between orbitals that are side-by-side.

sp Orbital

Composed of one s and one p orbital; can hold four electrons. Linear.

Linear

Arrangement of two objects around a central atom. Non-polar.

Bent

Occurs when one non-bonding pairs and two atoms are arranged around a central atom. Polar.

Tetrahedral

Arrangement of four objects around a central atom. Non-polar.

Trigonal Pyramidal

Occurs when three atoms and one non-bonding pair is arranged around a central atom. Polar.

Silicon Dioxide

Has a unique structure; O-Si-O bonds are always 109.5°.

Formal charge

V - N - (B/2) where V = total valence e⁻, N = non-bonding e⁻, and B = bonding e⁻.

Isomer

Two molecules that are composed of the same type and number of elements but are arranged in different ways and have different properties are isomers.

Combustion of a Hydrocarbon

CxHy + (x + y/4)O₂ → xCO₂ + y/2H₂O

Molar Volume

(Vm) The volume occupied by one mole of a substance.

Molar Volume of an Ideal Gas

22.414 L/mol @ STP

Limiting Reagent

The component of a chemical reaction that will be completely used up first.

Atomic Mass

Can be g/mol, kg/kmol, mg/mmol, etc.

Specific Heat

The amount of heat required to raise the temperature of one gram of a substance by one °C. (units: J x g⁻¹ x °C⁻¹)

Heat (J)

mass (g) x specific heat (J x g⁻¹ x °C⁻¹) x ΔT (°C)

Molar Heat Capacity

Same as specific heat, but requirement for raising 1 mole of a substance by one °C.

Bond Energy

The energy required to break a bond, and the energy released when a bond is formed.

Bomb Calorimeter

An insulated container used to study reactions at a constant volume.

Calorimeter Constant

Amount of energy required to raise the water surrounding the chamber of the bomb calorimeter by one °C

Gibbs Free Energy

ΔG = ΔH - TΔS, where ΔH = change in enthalpy and ΔS = change in entropy.

Enthalpy

change in energy of a system.

Entropy

change in chaos of a system.

Free Energy

change in spontaneity of a system.

Boiling Point

The point at which the vapor pressure of a liquid equals 1 atm.

Normal Melting Point

The temperature at which the solid and liquid phases of a substance are in equilibrium at atmospheric pressure (760 mm Hg).

Graham's Law of Effusion

The lighter a gas's atomic weight, the faster it will escape a container.

Molarity

mols/L; mmols/mL