Langara College Chemistry (CHEM 1114/1118/1120) in University
A large part of first-year university chemistry is about energy and reactions — how much heat a reaction releases or absorbs, why acids and bases behave as they do, and how chemistry generates and responds to electricity. These topics feel more concrete than atomic theory, but they carry their own conceptual challenges and a good deal of calculation, and they are where a significant share of exam marks live. Understanding the principles behind thermochemistry, acid-base chemistry, and electrochemistry — rather than memorising equations — is what turns this substantial part of the course from daunting into manageable.
This guide covers the energy-and-reactions half of university chemistry — thermochemistry, spontaneity, acids and bases, solutions, and electrochemistry — so these heavily-tested, calculation-rich topics become something you can reason through clearly rather than dread on exam day.
Thermochemistry: the energy of reactions
Every chemical reaction involves a change in energy, and thermochemistry is the study of that energy — primarily heat. The central quantity is enthalpy change, and its sign tells the essential story: an exothermic reaction releases heat and has a negative enthalpy change, while an endothermic reaction absorbs heat and has a positive one. Combustion is exothermic; melting ice is endothermic. This simple sign convention underlies a large body of calculation and reasoning.
A powerful principle that university chemistry emphasises is that enthalpy is a state function — the total energy change of a reaction depends only on the starting and ending states, not the path taken between them. This is Hess's law, and it is enormously useful: it means you can calculate the enthalpy change of a reaction you cannot easily measure by adding up the enthalpy changes of reactions you can, as long as they combine to give the overall reaction. Understanding enthalpy, the exothermic-endothermic distinction, and the path-independence that makes Hess's law work is the core of thermochemistry, and it rewards conceptual understanding as much as calculation.
Acids and bases: the chemistry of pH
Acid-base chemistry is one of the most important and most tested topics in first-year chemistry, and it centres on the concept of pH — a measure of how acidic or basic a solution is. The crucial thing to understand is that pH is a logarithmic scale: it is the negative logarithm of the hydrogen-ion concentration, so each unit of pH represents a tenfold change in acidity, not a small linear step.
This has real consequences. A hydrogen-ion concentration of gives a pH of 3, and a solution at pH 3 is a thousand times more acidic than one at pH 6 — three factors of ten, not twice as acidic. The companion relationship, , ties acidity and basicity together, with pH 7 as neutral, below 7 acidic, and above 7 basic. Reasoning correctly about this logarithmic scale, rather than treating pH as an ordinary number, is where many students lose marks, and getting it right is foundational to the whole topic.
Strong versus weak, and why it matters
A distinction that university chemistry treats carefully is between strong and weak acids and bases. A strong acid dissociates completely in water — every molecule gives up its hydrogen ion — while a weak acid only partially dissociates, existing in equilibrium with its undissociated form. This is not a matter of concentration but of the intrinsic tendency to dissociate, and confusing the two is a common error.
The distinction matters because it changes how you calculate pH and how a solution behaves. Weak acids and bases, existing in equilibrium, give rise to buffers — solutions that resist changes in pH — which are crucial in chemistry and biology alike, and which connect acid-base chemistry to the equilibrium principles elsewhere in the course. Understanding that strength refers to the degree of dissociation, and reasoning about the equilibrium that weak acids and bases establish, is what lets you handle the more sophisticated acid-base problems the course sets. It is a place where genuine understanding of the underlying chemistry clearly outperforms memorised procedures.
If the energy-and-reactions topics — thermochemistry, pH and acids, electrochemistry — are where your chemistry course is challenging you, understanding the principles behind the calculations is what makes them click. Our university chemistry tutoring builds exactly this reasoning, working from your real problems and past exams.
Spontaneity: what makes a reaction go
Thermochemistry leads naturally to one of the deepest questions in chemistry: what determines whether a reaction happens on its own? It is tempting to think exothermic reactions are always spontaneous, but that is not quite right — the full answer involves both energy and disorder. Entropy, a measure of the disorder or number of ways a system can be arranged, matters alongside enthalpy, and nature tends toward states of both lower energy and higher entropy.
The two factors combine in the concept of free energy, which determines spontaneity: a reaction proceeds on its own when it decreases free energy, which balances the enthalpy change against the entropy change at a given temperature. This is why some endothermic reactions still happen spontaneously — because they increase entropy enough to compensate — and why temperature can change whether a reaction is spontaneous. Understanding that spontaneity depends on both energy and disorder, not energy alone, is a genuine conceptual step and one that connects thermochemistry to equilibrium and to the direction of chemical change. It is exactly the kind of principle that rewards understanding over memorised rules.
Solutions and concentration
Much of university chemistry, and nearly all of acid-base and electrochemistry, happens in solution, so understanding solutions is foundational. A solution is a homogeneous mixture, and its concentration — how much solute is dissolved in how much solvent — is expressed most often as molarity, the number of moles of solute per litre of solution. Being fluent with concentration and able to convert between the ways it is expressed is assumed throughout the course.
Concentration matters because it directly affects chemical behaviour: reaction rates, the position of equilibria, pH, and the properties of solutions all depend on it. Calculations involving preparing solutions, diluting them, and relating concentration to the amounts reacting are pervasive, and they build on the stoichiometry from earlier chemistry. Understanding solutions and concentration well, and being comfortable with the calculations, removes a source of friction that otherwise slows students down across acid-base, equilibrium, and electrochemistry problems alike. It is a practical foundation that pays off continuously, and one worth making genuinely automatic.
Electrochemistry: chemistry and electricity
Electrochemistry connects chemical reactions to electricity, and it rests on the concept of oxidation and reduction — redox reactions — in which electrons are transferred between substances. Oxidation is the loss of electrons and reduction is the gain, a pairing students remember with the mnemonic 'OIL RIG': oxidation is loss, reduction is gain. Because electrons are transferred, these reactions can drive or be driven by an electric current, which is the basis of batteries and of processes like electroplating.
In an electrochemical cell, oxidation happens at the anode and reduction at the cathode, and the flow of electrons between them constitutes the current. A spontaneous reaction — one that proceeds on its own, as in a battery — corresponds to a positive cell potential, which measures the driving force of the reaction. Balancing redox reactions requires conserving both mass and charge, which is more involved than balancing ordinary equations and is a frequent exam challenge. Understanding electrochemistry as electron transfer that can be harnessed as electricity, and reasoning carefully about oxidation, reduction, and cell potential, ties the topic together and connects the chemistry you study to the batteries and technologies that run on it.
Where students struggle with energy and reactions
- Confusing the sign convention for exothermic and endothermic reactions.
- Treating pH as a linear scale rather than a logarithmic one.
- Confusing acid strength (dissociation) with concentration.
- Mixing up oxidation and reduction, or which happens at which electrode.
- Struggling to balance redox reactions by conserving mass and charge.
How to master energy and reactions
- Learn the enthalpy sign convention and use Hess's law's path-independence.
- Reason about pH as a logarithmic scale, and use pH + pOH = 14.
- Understand acid strength as degree of dissociation, and the equilibria of weak acids.
- Master oxidation and reduction, and the anode-cathode roles in a cell.
- Practise balancing redox reactions by conserving both mass and charge.
- Remember spontaneity depends on both energy and entropy, not enthalpy alone.
Master the energy side of chemistry
If thermochemistry, acids and bases, or electrochemistry are the topics standing between you and a strong chemistry grade, understanding their principles turns the calculations from daunting into routine. Our university chemistry tutoring in Burnaby and online builds that understanding from your own course and past exams, for science and engineering students.
Start with a free conversation. Book a free 30-minute consultation, tell us which topic is hard and why, and we will show you the reasoning that unlocks it — online across Metro Vancouver and beyond, or in person in Burnaby. Honest advice included on whether tutoring fits your goals.