REACTIONS & BALANCING
This law states that atoms cannot be created or destroyed in a reaction.
Law of Conservation of Mass
According to Lewis rules, the central atom is usually the one with this characteristic.
least electronegative atom (besides hydrogen)
This term refers to the mass of one molecule of a substance expressed in grams.
mass of one molecule (molar mass ÷ Avogadro’s number)
These are the weakest intermolecular forces, caused by random fluctuations in electron density.
London dispersion forces
Monoatomic anions are named by replacing the end of the element with this suffix.
–ide
Formation of bubbles during a reaction is evidence of this type of change.
gas formation
Formal charge is calculated using this formula:
(valence e⁻) − (lone-pair e⁻) − ½(bonding e⁻)
117 g of NaCl contains 1.20 × 10²⁴ formula units.
This is because 117 g corresponds to this many moles of NaCl.
2.00 mol
Between pentane and 2-methylbutane (same formula), pentane has the higher boiling point because of this difference.
larger surface area → stronger LDFs
The prefix that corresponds to five in covalent naming.
penta-
The balanced equation for propane combustion (C₃H₈ + O₂ → CO₂ + H₂O) requires this many O₂ molecules.
5 O₂
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
NO is an example of a molecule that breaks the octet rule for this specific reason.
odd number of electrons
These metal ions never require Roman numerals in naming because they have fixed charges: Al³⁺, Zn²⁺, and this third ion.
Ag⁺
Water is less dense as a solid than as a liquid due to this hydrogen-bond-related phenomenon.
open lattice structure
The correct formula for calcium nitrate is written this way.
Ca(NO₃)₂
When two compounds exchange ions to form two new compounds, this type of reaction has occurred.
double-replacement reaction
A molecule with five electron domains and two lone pairs adopts this molecular geometry.
T-shaped
This is the strongest intermolecular force present in liquid NH₃.
hydrogen bonding
At this point on a phase diagram, the liquid and gas phases become indistinguishable.
critical point
Copper(II) sulfate contains Cu²⁺ and SO₄²⁻. Its formula is this.
CuSO₄
In the balanced reaction 4Fe + 3O₂ → 2Fe₂O₃, the O₂ coefficient is 3 because of this stoichiometric requirement.
balancing both Fe and O atoms simultaneously to satisfy conservation of mass
SF₆ violates the octet rule because sulfur can hold more than eight electrons once it reaches this period of the periodic table.
period 3 or higher
Carbon exists as C-12 and C-13 isotopes, yet the periodic table lists a weighted average atomic mass of 12.01 amu. This average mass is weighted by this factor.
natural isotopic abundance
A substance at a temperature/pressure where all three phases coexist is located at this point on the phase diagram.
triple point
The covalent compound dinitrogen tetroxide has this formula.
N₂O₄