Kinematics and Equilibria

A comprehensive set of flashcards covering key concepts in Kinematics and Equilibria, designed for exam preparation.

What is the rate of reaction?

The change in concentration of a reactant or product over time.

What are the units for rate of reaction?

mol dm³ s⁻¹

What does the rate constant (k) represent?

A proportionality constant specific to a reaction at a particular temperature.

What is the order of reaction?

The power to which the concentration of a reactant is raised in the rate equation.

Define half-life (t½).

The time taken for half the amount of a reactant to be used up.

What is activation energy (Ea)?

The minimum energy required for a reaction to occur.

What is the rate-determining step?

The slowest step in a reaction mechanism that limits the overall rate.

What is catalysis?

Substances that increase the rate of a reaction by lowering the activation energy without being consumed.

According to Collision Theory, what conditions must be met for a reaction to occur?

Particles must collide with sufficient energy (≥ Ea) and with correct orientation.

What are enzymes?

Biological catalysts that speed up biochemical reactions under mild conditions.

How does concentration affect reaction rates?

Higher concentration of reactants leads to more frequent collisions.

How does temperature affect reaction rates?

Higher temperatures increase kinetic energy, leading to more collisions with Ea.

What role do catalysts play in reaction rates?

They provide alternative reaction pathways with lower activation energy.

How does surface area affect reaction rates?

Finer particles provide more collision sites.

What effect does pressure have on gas reaction rates?

Increased pressure increases particle density, resulting in more frequent collisions.

What is the general rate equation?

Rate = k [A]ⁿ [B]ᵐ.

In the rate equation, what does n and m represent?

The orders with respect to A and B.

If doubling [A] quadruples the rate, what is the order with respect to A?

Second order.

What is the zero order in reaction rates?

Rate is independent of concentration.

What characterizes first order reactions?

Rate is proportional to [A].

How can one deduce the order of reaction from data?

Use initial rates or graphical methods.

How is the initial rate calculated on a graph?

It is the slope of the tangent at time t = 0 on the concentration vs time graph.

What is the formula for half-life of first order reactions?

t½ = 0.693/k.

What is dynamic equilibrium?

Occurs in closed systems where forward and reverse reactions occur at equal rates.

What remains constant at dynamic equilibrium?

Concentrations of reactants and products remain constant, not necessarily equal.

What characterizes the macroscopic properties at equilibrium?

They remain constant.

Does changing concentration affect the value of K?

No.

What happens when concentration increases according to Le Chatelier's principle?

The position of equilibrium shifts to oppose the change.

What occurs when pressure is changed in reactions with different moles of gas?

The position of equilibrium shifts to the side with fewer gas molecules.

How does temperature affect the value of K?

It changes the value of K; increasing temperature favors endothermic reactions.

What is the effect of increasing temperature on an endothermic reaction?

Shifts the position of equilibrium to the right.

What is the effect of increasing temperature on an exothermic reaction?

Shifts the position of equilibrium to the left.

What does Kc relate to?

Concentration: Kc = [Products]ⁿ/[Reactants]ᵐ.

What does Kp relate to?

Partial pressures: Kp = (Pproducts)ⁿ/(Preactants)ᵐ.

What is Le Chatelier’s principle?

If a system at equilibrium is disturbed, it will adjust to counteract the change.

How does the addition of a common ion affect solubility?

Reduces solubility by shifting equilibrium to the left.

What does Ka represent?

Acid dissociation constant.

What does Kb represent?

Base dissociation constant.

What is Kw?

Ionic product of water = 1 × 10⁻¹⁴ at 25°C.

How is pH calculated?

pH = −log[H⁺].

What is the Henderson-Hasselbalch equation?

pH = pKa + log([A⁻]/[HA]).

What is a buffer?

A solution that resists changes in pH when small amounts of acid or base are added.

What is the effect of temperature on Kc or Kp?

Temperature changes Kc/Kp; increases if favoring endothermic reaction.

What do strong acids do in solution?

Fully dissociate.

What do weak acids do in solution?

Partially dissociate.

According to Bronsted-Lowry theory, what is an acid?

A proton donor.

According to Bronsted-Lowry theory, what is a base?

A proton acceptor.

What is a strong base?

A base that fully dissociates in solution.

How is the acid dissociation constant (Ka) derived?

K1 = [H⁺][A⁻]/[HA].

How is the base dissociation constant (Kb) derived?

Kb = [BH⁺][OH⁻]/[B].

Explain the concept of solubility product (Ksp).

Ksp is the solubility product constant of a sparingly soluble salt.

In Ksp calculations, what affects Ksp?

The concentration of the ions in the saturated solution.

What principle explains the reaction of weak acids with bases?

Amphoteric behavior.

What are the components of a successful acid-base indicator?

Change color sharply at or near the equivalence point in titration.

Why choose phenolphthalein for strong acid-strong base titrations?

It has an obvious color change in the relevant pH range.

What happens when strong acids meet weak bases in titration?

Phenolphthalein is unsuitable; methyl orange is preferred.

What occurs during the neutralization of strong acids and bases?

Formation of water and a salt.

What type of molecules predominantly make up weak acids and bases?

Mostly molecular.

What are the trends for reactivity among Group II elements?

Reactivity increases down the group due to ease of ionization.

What are the general reactions of Group II elements with oxygen?

They form oxides when they react with oxygen.

Describe the thermal stability of Group II carbonates.

Stability increases down the group.

What is the thermal decomposition reaction of nitrates in Group II?

Nitrates decompose to oxides, NO₂, and O₂.

What do soluble sulfates exhibit down Group II?

Solubility decreases down the group.

What are amphoteric oxides?

Oxides that can react with both acids and bases.

Give an example of a basic oxide.

Sodium oxide (Na₂O).

Give an example of an acidic oxide.

Silicon dioxide (SiO₂).

What are the properties of silicon(IV) oxide (SiO₂)?

Giant covalent lattice, high melting point, and insoluble in water.

What kinds of bonding does silicon(IV) oxide exhibit?

Covalent bonding.

How do metallic character and melting points trend down Group IV?

Metallic character increases, and melting point decreases.

What happens to reactivity in group VII elements down the group?

Reactivity decreases down the group.

What distinguishes strong acids from weak acids?

Strong acids completely dissociate in solution, while weak acids do not.

How are halogens characterized?

All halogens exist as diatomic molecules (X₂).

What happens to bond strength in hydrogen halides down the group?

Bond strength decreases, making them less thermally stable.

Explain the importance of identifying cations through flame tests.

Different metal ions emit different colors when heated in a flame.

What do you expect to observe with copper(II) during a flame test?

Blue-green flame color.

Why do we use reagents like NaOH and NH₃ for identifying cations?

To form precipitates that indicate the presence of specific metal ions.

What color does barium yield in a flame test?

Pale green.

What is the confirmatory test for Cl⁻?

White precipitate with AgNO₃, dissolving in dilute NH₃.

Summarize the behavior of halides with silver nitrate.

They form precipitates of AgX based on their solubilities.

What indicates a positive result for carbonate ions?

Effervescence when diluted HCl is added.

What ions are involved in the carbonate test?

CO₃²⁻ ions.

How can one determine the presence of sulfate ions?

By adding Ba²⁺ ions to form a white precipitate of BaSO₄.

What is the significance of the color changes in vanadium oxidation states?

Identifies oxidation states via color transitions.

What can be inferred from the standard electrode potentials of halogens?

Higher E° indicates a stronger oxidizing agent.

What is the purpose of ligand exchange in transition metal complexes?

To replace one ligand with another in a complex ion.

What are the observations during hydrolysis of SnCl₄?

Steamy HCl fumes and white precipitate.

How does a disproportionation reaction occur in chlorine with NaOH?

Chlorine is both oxidized and reduced.

Which halogen has the highest E° value?

Fluorine (F₂) with +2.87 V.

How does the inert pair effect influence the oxidation states in heavier group elements?

Makes +2 oxidation state more stable.

How are different colored ions formed in transition metals?

d-electrons absorb light and undergo d-d transitions.

What is the unique aspect of lead(IV) chloride?

It decomposes easily compared to lead(II) chloride.

What does the reaction of magnesium and acid produce?

Hydrogen gas and a salt.

What happens during the reaction of alkaline earth metals with water?

Formation of hydroxides and hydrogen gas.

What techniques allow for differentiation between cations?

Flame tests and precipitation reactions.

When testing for sulfate, what observation indicates a positive result?

Formation of a white precipitate with barium chloride.

What color precipitate is formed from the reaction of AgNO₃ with iodide ions?

Yellow precipitate of AgI.

What principle is applied in the formation of complexes and precipitation?

Le Chatelier's Principle.

Identify the equation indicating the reaction of carbonate ions with acid.

CO₃²⁻ + 2H⁺ → CO₂ + H₂O.

What is the significance of ammonium ion tests?

Detection through the evolution of ammonia gas.

Summarize the gasses evolved during the reaction of nitrate ions with metals.

Ammonia gas is produced.