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SingaporeChemistry

Physical Chemistry

11 dot points across 11 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How is the electronic structure of an atom deduced, and how does it explain ionisation energy patterns?

Describe the structure of the atom in terms of protons, neutrons and electrons, deduce electronic configurations using s, p and d subshells, and explain successive and periodic ionisation energy trends in terms of nuclear charge, shielding and subshell energies
A focused answer to the H2 Chemistry learning outcome on atomic structure. Subatomic particles, the s/p/d filling order, writing configurations including the Cr and Cu anomalies, and using successive and first ionisation energy data as evidence for shells and subshells.
9 min answer →

How do the type of bonding and the shape of a molecule arise from electron arrangement, and how do they control physical properties?

Describe ionic, covalent (including dative) and metallic bonding, predict molecular shapes and bond angles using VSEPR, account for bond polarity and overall polarity, and relate intermolecular forces (van der Waals, hydrogen bonding) to physical properties
A focused answer to the H2 Chemistry learning outcome on bonding and shape. Ionic, covalent, dative and metallic bonding, using VSEPR to predict shapes and bond angles, bond and molecular polarity, and how van der Waals forces and hydrogen bonding govern boiling points and solubility.
10 min answer →

How are enthalpy changes defined, measured and calculated, and what controls whether a reaction is energetically favourable?

Define standard enthalpy changes (formation, combustion, neutralisation, atomisation, lattice energy, hydration, solution), apply Hess's law and Born-Haber cycles, and use the relationship between enthalpy, entropy and Gibbs free energy to judge feasibility
A focused answer to the H2 Chemistry learning outcome on energetics. Standard enthalpy definitions, Hess's law cycles, Born-Haber cycles for lattice energy, the entropy change of a reaction, and using Gibbs free energy to decide feasibility.
11 min answer →

How is the position of a dynamic equilibrium described quantitatively, and how does it respond to changing conditions?

Explain dynamic equilibrium and write expressions for Kc and Kp, calculate equilibrium constants and equilibrium amounts, and apply Le Chatelier's principle to predict the effect of concentration, pressure, temperature and catalysts on the position of equilibrium
A focused answer to the H2 Chemistry learning outcome on equilibrium. Dynamic equilibrium, writing and calculating Kc and Kp, the ICE-table method, the effect of changing conditions through Le Chatelier's principle, and why a catalyst does not shift the position.
11 min answer →

How do standard electrode potentials predict the direction and feasibility of redox reactions, and how is electrolysis quantified?

Define standard electrode potential, calculate standard cell potential and use it to predict the feasibility of redox reactions, describe the effect of concentration qualitatively, and apply Faraday's laws to electrolysis calculations
A focused answer to the H2 Chemistry learning outcome on electrochemistry. Standard electrode potential and the hydrogen electrode, calculating cell potential and predicting redox feasibility, the qualitative effect of concentration, and Faraday's laws applied to electrolysis.
11 min answer →

How are acid and base strength, pH and buffering described quantitatively?

Apply the Bronsted-Lowry theory, distinguish strong and weak acids and bases using Ka, Kb and pKa, calculate pH of strong and weak acids and of buffers, explain buffer action, and interpret titration curves and indicator choice
A focused answer to the H2 Chemistry learning outcome on ionic equilibria. Bronsted-Lowry acids and bases, Ka and pKa for weak acids, calculating pH of strong and weak acids, buffer action and the Henderson-Hasselbalch relationship, titration curves and indicator selection.
12 min answer →

What controls how fast a reaction goes, and how can the rate equation reveal the mechanism?

Explain rate of reaction using collision theory and the Boltzmann distribution, deduce rate equations and orders from experimental data, define the rate constant and half-life, and use the rate-determining step to propose a reaction mechanism, including the action of catalysts
A focused answer to the H2 Chemistry learning outcome on kinetics. Collision theory and the Boltzmann distribution, deducing order and the rate constant from data, half-life of a first-order reaction, the rate-determining step, and how catalysts (including enzymes) lower activation energy.
11 min answer →

How are oxidation and reduction tracked, balanced and recognised across inorganic and organic chemistry?

Assign oxidation numbers, define oxidation and reduction in terms of electron transfer and oxidation-number change, identify oxidising and reducing agents, and construct balanced redox equations from half-equations
A focused answer to the H2 Chemistry learning outcome on redox. Rules for assigning oxidation numbers, defining oxidation and reduction by electron transfer and oxidation-number change, recognising oxidising and reducing agents, and balancing redox equations from half-equations.
9 min answer →

How is the solubility of a sparingly soluble ionic compound described and predicted?

Define and write expressions for the solubility product Ksp, calculate solubility from Ksp and vice versa, predict precipitation by comparing the ionic product with Ksp, and explain the common ion effect
A focused answer to the H2 Chemistry learning outcome on solubility equilibria. Defining and writing Ksp, converting between Ksp and molar solubility, using the ionic product to predict precipitation, and explaining the common ion effect quantitatively.
9 min answer →

How does the ideal gas equation describe gas behaviour, and when and why do real gases deviate from it?

State the ideal gas equation pV = nRT and use it in calculations including determination of molar mass, explain the assumptions of the kinetic theory, and account for the deviation of real gases from ideal behaviour at high pressure and low temperature
A focused answer to the H2 Chemistry learning outcome on gases. Using the ideal gas equation to find molar mass, the assumptions of kinetic theory, and a clear account of why real gases deviate at high pressure and low temperature in terms of molecular volume and intermolecular forces.
8 min answer →

How is the mole used to connect masses, volumes and concentrations in chemical calculations?

Define the mole and the Avogadro constant, interconvert mass, amount, gas volume and solution concentration, and apply stoichiometry including limiting reagent, percentage yield and atom economy and titration calculations
A focused answer to the H2 Chemistry learning outcome on the mole and stoichiometry. The Avogadro constant, interconverting mass, moles, gas volume and concentration, limiting reagent and yield, atom economy, and the structure of a titration calculation.
9 min answer →