The pH scale

This is an introduction to the pH scale. Explore the relationship between pH and hydrogen ion (H⁺) concentration. Download PDF

Catalyst and Activation Energy

Catalyst A catalyst is a substance that speeds up a chemical reaction but it does not undergo a chemical reaction itself. The catalyst allows the reaction an alternative pathway to take place. The catalyst does not lower the activation energy of the reaction. Analogy

Bond Energy and Bond Enthalpy

Bond Enthalpy Introduction In order to understand why breaking bonds requires energy (endothermic) and making bonds releases energy (exothermic), one must first understand the nature of a chemical bond and why it occurs in the first place. Remember that bonds are due to the exchange or sharing of electrons between atoms. Forming bonds is a […]

Reaction enthalpies

Enthalpy change For a reaction Bonds Know that Breaking bonds always requires energy (never releases energy) Forming bonds always releases energy (never requires energy) Exothermic and endothermic process Breaking bonds is always an endothermic process (whether breaking single, double or triple bonds). Forming bonds is an exothermic process (whether making single, double or triple bonds). However, […]

6. Reaction Coordinate Diagram

Given the following reaction, sketch a reaction coordinate graph. The reaction involves two steps, step 1 is the slowest step and step 2 is the fastest step. Indicate on the diagram the overall enthalpy change of the reaction, the reaction for the transitions states and intermediate states.

H2(g) + 2ICl(g) –> 2HCl(g) + I2(g)

5. Memorizing the names of Polyatomic ions

   Examples of polyatomic ions Generally, polyatomic ions have suffixes that end in “ite” or “ate” if they contain oxygen atoms.  Chloride shown below is not a polyatomic ion, it’s a monoatomic ion consisting of only one atom. chloride hypochlorite chlorite chlorate perchlorate Examples of other polyatomic ions: OH⁻ (hydroxide) CN⁻ (cyanide) CH3COO−or C2H3O2 − […]

1. Naming inorganic compounds

Identify if a compound is covalent or ionic You will need to know the periodic table You must be able to identify the non-metals, metals, and transition elements in the periodic table You must be able to categorize a compound as ionic or covalent formed from elements based on their location within the periodic table […]

2. Learn the rules for covalent compounds

  Covalent compound A covalent compound involves the sharing of electrons between two non-metals. Rules What are the rules for naming covalent compounds? Covalent compounds use prefixes – to indicate the number of atoms of each element in the compound The element that is on the left of the periodic table comes first The element […]

5. Mechanisms and Intermediates

Reaction mechanism Chemical reactions often take place in multiple steps and it’s not always obvious from looking at the chemical equation. For example, the decomposition of ozone: From the equation, it appears that O₃ decomposes to O₂ in one step. In reality, it’s more likely to take place in the following sequence: The above shows […]

1. Introduction to Chemical Kinetics

Energy Kinetics involves studying what makes chemical reactions happen. Every reaction that happens involves some energy exchange, whether it’s slow reaction such as iron rusting, or a faster reaction, such as when a rocket burns fuel during take off.  Size of particles Pictures in the slider: (CC BY-SA 3.0) | Link: | Author: Hans-Peter […]