Physical Chemistry Flashcards
(36 cards)
What is the definition of electrostatic forces?
Attractive forces between charged particles
Electrostatic forces are fundamental forces that arise from the interaction of charged particles.
How does charge size affect electrostatic force?
The bigger the charge, the larger the electrostatic force
This principle applies to both positive and negative charges.
What are dipoles in chemistry?
Molecules that have a positive and negative end
Dipoles can be non-polar or polar depending on the distribution of charge.
What are London dispersion forces?
Weak intermolecular forces present in non-polar molecules
These forces arise from temporary dipoles that occur when electrons are distributed asymmetrically.
Which molecules exhibit hydrogen bonding?
H2O, HF, NH3
Hydrogen bonds are a specific type of dipole-dipole interaction that occurs when hydrogen is bonded to highly electronegative atoms.
What are the types of intermolecular forces listed?
- Ion-ion
- Ion-dipole
- Dipole-dipole
- Hydrogen bonding
- London dispersion forces
These forces determine the physical properties of substances.
Fill in the blank: __________ forces are weak intermolecular forces due to temporary dipoles.
London dispersion
These forces are also known as Van der Waals forces.
True or False: All polar molecules can form hydrogen bonds.
False
Not all polar molecules have the necessary hydrogen atoms bonded to highly electronegative atoms for hydrogen bonding.
What is a characteristic of polar molecules?
They have regions of partial positive and negative charge
This uneven distribution of charge leads to dipole moments.
What is the significance of electronegativity in molecular polarity?
Electronegativity determines the distribution of electron density in a molecule
Higher electronegativity leads to stronger dipoles.
What is the rate of a reaction when the order is 0?
Changing concentration doesn’t affect the rate of reaction.
A zero-order reaction has a constant rate that is independent of the concentration of the reactants.
What does an order of 1 indicate about the rate of reaction?
Doubling the concentration doubles the rate.
In a first-order reaction, the rate is directly proportional to the concentration of one reactant.
What is the implication of an order of 2 in a reaction?
Doubling the concentration quadruples the rate.
In a second-order reaction, the rate is proportional to the square of the concentration of the reactants.
What is the overall order of a reaction with individual orders m and n?
Overall order = m + n.
The overall reaction order is the sum of the powers to which the concentration terms are raised in the rate law.
What is entropy in the context of a reaction?
Entropy is when a reaction is spontaneous or possible.
A spontaneous reaction tends to increase the overall entropy of the system.
What favors a reaction to be spontaneous?
If ΔG < 0, the reaction is spontaneous.
The Gibbs free energy change (ΔG) indicates the spontaneity of a reaction; negative values suggest spontaneity.
What happens when a reaction is at equilibrium?
G is 0.
At equilibrium, the Gibbs free energy change is zero, indicating no net change in the concentrations of reactants and products.
Fill in the blank: The rate of a reaction is just feasible when G is _______.
This indicates that the reaction can proceed in either direction at equilibrium.
What do acids donate in a solution?
H+ ions
Acids are defined by their ability to donate protons (H+ ions) in a solution.
What are bases according to Bronsted-Lowry theory?
Proton acceptors
Bases are substances that accept protons in a chemical reaction.
What are Lewis acids and bases defined as?
Electron pair acceptors and donors
Lewis theory expands the definitions of acids and bases to include electron pair transfer.
What is the dissociation constant represented by ‘Ka’?
Acid dissociation constant
Ka indicates the strength of an acid in solution, reflecting its tendency to donate protons.
What is the relationship between pKa and Ka?
pKa = -log(Ka)
pKa is a logarithmic scale used to express the acidity of a solution, where lower pKa values indicate stronger acids.
What is the pH of pure water at room temperature?
7
At room temperature, pure water is neutral with a pH of 7.
