Chemistry: Reactions, Thermodynamics, and Atomic Structure Key Concepts

What are precipitation reactions?

Chemical reactions that result in the formation of a solid.

Which substances are always soluble according to solubility rules?

Alkali metals, nitrates, and ammonium.

What characterizes acid-base reactions?

The transfer of a proton (H+) from an acid to a base.

What is a common product of acid-base reactions?

Water (H2O).

What is the significance of strong acids and bases in water?

They fully dissociate in water.

What does LEO GER stand for in redox reactions?

LEO: Lose Electrons Oxidized; GER: Gain Electrons Reduced.

What is the purpose of writing half-reactions in redox reactions?

To show oxidation and reduction separately.

How do you determine if a single replacement reaction will occur?

Use an activity series.

What is the general form of a double replacement reaction?

AX + BY → AY + BX.

What are the products of gas-forming reactions involving H2CO3?

H2O(l) + CO2(g).

What is a net ionic equation?

An equation that shows only the ions that participate in the reaction, excluding spectator ions.

What is the purpose of titrations in quantitative analysis?

To measure the amount of one reactant needed to consume another.

What is the equivalence point in a titration?

The point at which the amount of titrant added is enough to completely neutralize the analyte.

What is gravimetric analysis?

A method that involves forming a precipitate, filtering, drying, and measuring its mass.

What is the outcome of combustion analysis?

Burning a hydrocarbon generates CO2 and H2O.

What does the first law of thermodynamics state?

Heat is neither created nor destroyed; it can only be transferred.

What does a negative ΔH indicate?

An exothermic reaction that releases heat.

What is the formula for kinetic energy?

KE = (1/2) mv².

What is specific heat?

The amount of heat energy needed to raise 1g of a substance by 1°C.

How do you calculate heat transferred in a reaction using calorimetry?

q = mCΔT, where m is mass, C is specific heat, and ΔT is the change in temperature.

What happens to q when heat is absorbed?

q is positive.

What is constant volume calorimetry (bomb calorimetry) used for?

It measures the change in internal energy, typically used for combustion reactions.

What is the formula to calculate enthalpy change (ΔH) using standard enthalpy of formation (ΔHf)?

ΔH° = Σ ΔHf(products) - Σ ΔHf(reactants)

What is the significance of ΔHf for reactants or products in their elemental state?

The ΔHf of elements in their standard state is zero.

What does Hess's Law state about enthalpy changes?

It allows manipulation of ΔH data from other reactions to find the ΔH for a desired reaction.

What happens to the enthalpy if a chemical reaction is doubled?

The enthalpy is also doubled.

What are the parts of a wave in the electromagnetic spectrum?

Amplitude, frequency, wavelength, crest, and trough.

What is the mnemonic for the electromagnetic spectrum?

RMIVUXG (Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma ray).

What is the visible spectrum mnemonic?

ROY G. BIV (Red, Orange, Yellow, Green, Blue, Indigo, Violet).

What does the Rydberg equation calculate?

The energy of transitions between electron energy levels.

What principle states that electrons exist in orbitals?

Bohr's model of the atom.

What is the Heisenberg Uncertainty Principle?

It states that one cannot know both the exact position and velocity of a particle simultaneously.

What are the three rules for filling orbitals?

Aufbau Principle, Pauli Exclusion Principle, and Hund's Rule.

What does the Aufbau Principle dictate?

Electrons fill orbitals from low energy to high energy.

What is the Pauli Exclusion Principle?

Electrons in the same orbital must have opposite spins.

What is Hund's Rule?

Every degenerate orbital must have one electron before pairing begins.

How do you report electron configuration for ions?

Remove or add electrons starting from the highest energy level.

What is Coulomb's Law?

It describes the interaction between two charged particles, where like charges repel and opposite charges attract.

What is effective nuclear charge (Z_eff)?

It describes the influence the nucleus has on valence electrons.

What is ionization energy?

The energy required to remove an electron from an atom.

What is electron affinity?

The energy change when an atom gains an electron, typically exothermic.

What is electronegativity?

The tendency of an atom to attract shared electrons in a bond.