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, […]

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)

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 hypochlorite chlorite chlorate perchlorate Note: Chloride shown above is not a polyatomic ion, it’s a monoatomic ion consisting of only one atom. Examples of other polyatomic ions: Oxyanions Oxyanions are ions that contain […]

Compounds with Polyatomic Ions

What are polyatomic ions? Ions are formed when neutral atoms gain or lose electrons. Similarly, a polyatomic ion is formed when a neutral molecule gains or loses electrons. A polyatomic ion is a charged group of atoms covalently bonded together. Majority of the polyatomic ions are anions, meaning they are negatively charged. Ammonium is the […]