MOLECULAR SHAPES & GEOMETRY
This VSEPR geometry occurs when a central atom has 2 electron sets and 0 lone pairs.
What is linear?
These are the weakest intermolecular forces.
What are London dispersion forces?
This law states P₁V₁ = P₂V₂ at constant temperature.
What is Boyle's Law?
These are pairs of valence electrons not involved in bonding.
What are lone pairs?
This process describes gas particles escaping through a small opening.
What is effusion?
This molecular geometry has a tetrahedral electronic geometry but only 3 bonded atoms.
What is trigonal pyramidal?
This special strong dipole-dipole interaction.
What is hydrogen bonding?
This is the value of R in SI units in the ideal gas law .
0.0821 L·atm/mol·K
This term describes a bond where electrons are shared unevenly.
What is a polar covalent and ionic bond?
This is the volume occupied by 1 mole of any gas at Standard Temperature and Pressure (STP).
What is 22.4 Liters?
Determine the electronic and molecular geometry of carbon dioxide (CO₂).
Electronic = linear, Molecular = linear
Identify the strongest type of intermolecular force present between molecules of HCl.
What are dipole-dipole interactions?
A gas occupies 4.2 L at 25°C. Calculate its volume at 75°C if pressure remains constant.
4.9 L
Draw the Lewis structure for the carbonate ion (CO₃²⁻). How many total valence electrons does it have?
24 valence electrons
If 50.0 grams of NaHCO₃ decomposes (NaHCO₃(s) → NaOH(s) + CO₂(g)), how many moles of CO₂ are produced?
0.595 moles CO₂
Determine the electronic and molecular geometry for the carbon atom in formaldehyde, CH₂O.
Electronic = trigonal planar, Molecular = trigonal planar
Based on intermolecular forces, explain why H₂O is a liquid at room temperature while CH₄ is a gas.
Water has strong hydrogen bonding, while methane only has weak London dispersion forces.
A cylinder with a volume of 2.80 L has a pressure of 32.0 psi at 25.0 °C. If it is warmed to 75.0 °C, what is the new pressure?
37.3 psi
Draw the Lewis structure for PH₄⁺. What is the formal charge on the phosphorus atom?
Formal charge = +1
For the reaction 2 NaN₃(s) → 2 Na(s) + 3 N₂(g), what volume of N₂ gas is produced at 1.2 atm and 350 K from 15.0 grams of NaN₃?
6.6 L
A molecule has a tetrahedral electronic geometry and a bent molecular shape. Name a molecule that fits this description and state the number of lone pairs on the central atom.
What is water (H₂O)? It has 2 lone pairs on the central oxygen atom.
Arrange these from lowest to highest boiling point and justify your answer based on Van der Waals forces: CH₄, H₂O, N₂
N₂ (London) < CH₄ (London) < H₂O (Hydrogen Bonding)
How many moles of helium gas are in a 3.4-liter balloon at 1.05 atm and 25 °C? What is the mass of the gas in grams?
0.15 moles, 0.60 grams
Draw the two major resonance structures for the nitrite ion (NO₂⁻), show formal charges, and state the average charge on each oxygen atom.
The average charge on each oxygen atom is -½.
A 1.00-L cylinder of methane (CH₄) at 5,000 psi and 298 K is completely burned (CH₄ + 2O₂ → CO₂ + 2H₂O). First, find the moles of CH₄. Then, calculate the mass of CO₂ produced.
~14 moles CH₄, ~610 g CO₂