Leaving Cert Chemistry
26 guides on the parts of Leaving Cert Chemistry students reliably get wrong - the definitions that blur together, the steps that get skipped, and the reasoning an examiner expects to see. Each one names the mistake, explains why it happens, and gives you the correction.
Why Students Make Errors in Rates of Reaction
Rate depends on concentration, temperature and catalyst, and each acts for a different reason. Rates of reaction in Leaving Cert Chemistry.
Why Students Make Errors in Electrochemistry
Oxidation is loss and reduction is gain, but naming the electrode correctly is where the marks go. Electrochemistry for Leaving Cert Chemistry.
Why Students Make Errors in the Solutions Chapter of Chemistry
Concentration in moles per litre, in grams per litre, and in percentage are three different numbers. Solutions calculations for Leaving Cert Chemistry.
Common misconceptions about acids bases and pH levels
A strong acid and a concentrated acid are not the same thing. The acid and base distinctions Leaving Cert Chemistry marks you on.
Common misconceptions in calculating empirical formulas
Divide by the smallest, then scale to whole numbers. Where Leaving Cert Chemistry students stop one step short on empirical formula questions.
How to avoid errors when balancing complex chemical equations
Balance atoms, never change a formula to make the numbers work. The habit that fixes most Leaving Cert Chemistry equation errors.
How to correctly assign oxidation numbers in complex molecules
The rules have an order, and applying them out of order gives the wrong answer. Assigning oxidation numbers for Leaving Cert Chemistry.
How to easily understand the difference between Galvanic and Electrolytic cells
One produces electricity from a reaction, the other forces a reaction with electricity. Telling the two cell types apart in Leaving Cert Chemistry.
How to master equilibrium constants without memorization
Products over reactants, each raised to its coefficient. What the equilibrium constant actually tells you in Leaving Cert Chemistry.
How to master oxidation states without pure memorization
Oxidation states follow from electronegativity, not from a list to be learnt. Working them out rather than recalling them.
How to master Periodic Table trends without pure memorization
Atomic radius, ionisation energy and electronegativity all follow from the same two causes. Periodic trends for Leaving Cert Chemistry.
Why Students Confuse Mixtures and Compounds
A compound has fixed composition and new properties, a mixture has neither. The distinction Leaving Cert Chemistry expects you to justify.
Top Mistakes in Understanding States of Matter
Particle arrangement, spacing and movement change together between states. The states of matter comparisons Leaving Cert Chemistry asks for.
The biggest misconceptions about ideal gas laws and kinetic theory
Kelvin, not Celsius, and the reason why. Gas law calculations in Leaving Cert Chemistry and the assumptions behind them.
The most common mistakes in understanding VSEPR theory and molecular shapes
Lone pairs push harder than bonding pairs, which is what bends the shape. VSEPR and molecular shapes for Leaving Cert Chemistry.
The most frequent errors in stoichiometry calculations
Convert to moles first, use the ratio, then convert back. The stoichiometry sequence Leaving Cert Chemistry students skip steps in.
The most frequent mistakes in balancing redox reactions
Balance the electrons, not just the atoms. Redox balancing for Leaving Cert Chemistry, and the check that catches a wrong answer.
The truth about endothermic and exothermic reaction energy diagrams
Which way the arrow points, and where the activation energy sits. Reading energy profile diagrams in Leaving Cert Chemistry.
Understanding the real difference between ionic covalent and metallic bonds
Electrons transferred, shared, or pooled. Three bond types, three sets of properties, and the reasoning that links them.
Why calculating pH for weak acids and bases causes so many errors
A weak acid does not fully dissociate, so the simple pH formula does not apply. Weak acid calculations at Higher Level Leaving Cert Chemistry.
Why chemical bonding feels impossible and how to master it
Every bond type is atoms reaching a stable electron arrangement by a different route. Chemical bonding for Leaving Cert Chemistry.
Why drawing Lewis dot structures is harder than it looks
Count the valence electrons before drawing anything. The Lewis structure method that stops you guessing in Leaving Cert Chemistry.
Why Le Chateliers principle is actually easier than it looks
A system at equilibrium opposes whatever you do to it. Applying Le Chatelier to pressure, concentration and temperature changes.
Why Organic Chemistry Reactions Confuse Leaving Cert Students
Addition, substitution and elimination each change the carbon skeleton differently. Organic reaction types for Leaving Cert Chemistry.
Why students struggle to identify limiting and excess reactants
The limiting reactant is not the one you have least of, it is the one that runs out first. Working out which in Leaving Cert Chemistry.
Why the concept of moles and Avogadros number confuses beginners
A mole is a count, not a mass, and keeping that straight fixes most Leaving Cert Chemistry calculation errors.