Topic 1: Stoichiometric relationships

Flashcard 1

Question: Define the terms "mole" and "molar mass."

Answer:

Mole: The amount of substance that contains the same number of entities as there are atoms in exactly 12 grams of carbon-12.

Molar mass: The mass of one mole of a substance, expressed in grams per mole (g/mol).

Flashcard 2

Question: What is the Avogadro constant?

Answer: 6.022 x 10^23 mol^-1, which is the number of atoms, molecules, ions, or other entities in one mole of a substance.

Topic 2: Atomic structure

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Question: Describe the composition of an atom.

Answer: Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in orbitals.

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Question: What is the difference between an atom and an ion?

Answer: An atom is neutral, with the number of protons equaling the number of electrons. An ion is charged, with an unequal number of protons and electrons.

Topic 3: Periodicity

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Question: Explain the trend in atomic radius across a period and down a group.

Answer: Atomic radius decreases across a period due to increasing nuclear charge, and increases down a group due to the addition of energy levels.

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Question: Define ionization energy and state its periodic trend.

Answer: Ionization energy is the energy required to remove one mole of electrons from one mole of gaseous atoms. It generally increases across a period and decreases down a group.

Topic 4: Chemical bonding and structure

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Question: Describe the formation of an ionic bond.

Answer: An ionic bond is formed when one or more electrons are transferred from a metal to a non-metal, resulting in the formation of positive and negative ions that are attracted to each other.

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Question: Explain the concept of electronegativity.

Answer: Electronegativity is the ability of an atom to attract electrons in a covalent bond. It increases across a period and decreases down a group.

Topic 5: Energetics/Thermochemistry

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Question: Define enthalpy change.

Answer: Enthalpy change is the heat energy transferred in a reaction at constant pressure.

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Question: State Hess's Law.

Answer: Hess's Law states that the total enthalpy change for a reaction is the same regardless of the number of steps in the reaction or the way the reaction is carried out.

Topic 6: Chemical kinetics

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Question: Define the rate of reaction.

Answer: The rate of reaction is the change in concentration of a reactant or product per unit time.

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Question: Explain the effect of temperature on reaction rate.

Answer: Generally, an increase in temperature leads to an increase in reaction rate due to more frequent collisions and higher collision energies.

Topic 7: Equilibrium

Flashcard 13

Question: Define dynamic equilibrium.

Answer: Dynamic equilibrium is a state in which the rate of the forward reaction is equal to the rate of the reverse reaction and the concentrations of reactants and products remain constant.

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Question: State Le Chatelier's Principle.

Answer: Le Chatelier's Principle states that if a system at equilibrium is disturbed by a change in temperature, pressure, or concentration, the system will shift its equilibrium position to counteract the change.

Topic 8: Acids and bases

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Question: Define pH.

Answer: pH is a measure of the hydrogen ion concentration in a solution, calculated as the negative logarithm of the hydrogen ion concentration.

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Question: Describe the difference between a strong acid and a weak acid.

Answer: A strong acid completely dissociates into ions in solution, while a weak acid only partially dissociates.

Topic 9: Redox processes

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Question: Define oxidation and reduction.

Answer: Oxidation is the loss of electrons, while reduction is the gain of electrons.

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Question: Explain the role of oxidizing and reducing agents in redox reactions.

Answer: An oxidizing agent causes another substance to be oxidized and itself undergoes reduction. A reducing agent causes another substance to be reduced and itself undergoes oxidation.

Topic 10: Organic chemistry

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Question: Define a homologous series.

Answer: A homologous series is a series of organic compounds having the same functional group but with each successive member differing by CH2.

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Question: Explain the concept of structural isomerism.

Answer: Structural isomerism is the phenomenon where compounds have the same molecular formula but different structural arrangements of atoms.

Topic 11: Measurement and data processing

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Question: Define accuracy and precision in the context of measurements.

Answer: Accuracy refers to how close a measured value is to the true value, while precision refers to how close the measured values are to each other.

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Question: What is the difference between random and systematic errors?

Answer: Random errors are due to fluctuations in experimental conditions and can be reduced by averaging. Systematic errors are consistent and repeatable and can be reduced by calibration or correction.

Topic 12: Atomic structure

Flashcard 23

Question: What is the electronic configuration of magnesium (Mg)?

Answer: 1s² 2s² 2p⁶ 3s²

Flashcard 24

Question: Explain the concept of ionization energy.

Answer: Ionization energy is the energy required to remove an electron from a gaseous atom or ion.

Topic 13: Periodicity

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Question: Describe the trend in first ionization energy across period 3 (Na to Cl).

Answer: First ionization energy generally increases from left to right across period 3.

Flashcard 26

Question: Explain why atomic radius increases down a group.

Answer: Atomic radius increases down a group due to the addition of energy levels.

Topic 14: Bonding

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Question: Define covalent bond.

Answer: A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms.

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Question: Describe the bonding in a methane (CH₄) molecule.

Answer: Methane has four covalent bonds formed by sharing electrons between the carbon atom and each hydrogen atom.

Topic 15: Energetics/Thermochemistry

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Question: Define standard enthalpy change of reaction (ΔH°).

Answer: The standard enthalpy change of reaction is the enthalpy change when the molar quantities of reactants as shown in the chemical equation react under standard conditions.

Flashcard 30

Question: Calculate the enthalpy change for the reaction:

2H₂(g) + O₂(g) → 2H₂O(l) given the following bond energies (in kJ/mol): H–H (436), O=O (498), H–O (463).

Answer: Energy absorbed = (4 × H–O) - [(2 × H–H) + (1 × O=O)].

Topic 16: Chemical kinetics

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Question: Define the rate equation for a reaction.

Answer: The rate equation shows the relationship between the rate of reaction and the concentrations of reactants.

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Question: What is the effect of a catalyst on a reaction?

Answer: A catalyst increases the rate of reaction by providing an alternative reaction pathway with a lower activation energy.

Topic 17: Equilibrium

Flashcard 33

Question: Explain the concept of dynamic equilibrium.

Answer: Dynamic equilibrium is a state in which the rate of the forward reaction is equal to the rate of the reverse reaction and the concentrations of reactants and products remain constant.

Flashcard 34

Question: How does increasing the pressure affect the equilibrium position in a reaction involving gases?

Answer: Increasing the pressure favors the side of the reaction with fewer moles of gas.

Topic 18: Acids and bases

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Question: Define a conjugate acid-base pair.

Answer: A conjugate acid-base pair consists of two substances related by the loss or gain of a proton.

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Question: Calculate the pH of a 0.10 M solution of hydrochloric acid (HCl).

Answer: pH = -log[H⁺] = -log(0.10) = 1.0.

Topic 19: Redox processes

Flashcard 37

Question: Balance the following redox reaction:

Fe²⁺(aq) + MnO₄⁻(aq) + H⁺(aq) → Fe³⁺(aq) + Mn²⁺(aq) + H₂O(l).

Answer: 5Fe²⁺(aq) + MnO₄⁻(aq) + 8H⁺(aq) → 5Fe³⁺(aq) + Mn²⁺(aq) + 4H₂O(l).

Flashcard 38

Question: Identify the oxidizing agent and reducing agent in the following reaction:

2Fe(s) + 3Cl₂(g) → 2FeCl₃(s).

Answer: Oxidizing agent: Cl₂; Reducing agent: Fe.

Topic 20: Organic chemistry

Flashcard 39

Question: Define a functional group.

Answer: A functional group is a specific group of atoms within a molecule that is responsible for the characteristic chemical reactions of that molecule.

Flashcard 40

Question: Provide an example of an isomer of butane (C₄H₁₀).

Answer: Isobutane (2-methylpropane).