C5- Chemical Reactions

Enthalpy

Transfer of thermal energy during a chemical reaction 🌡️

Activation energy

The minimum energy that colliding particles have to react ⚡

Bond energy

The energy required to break a bond 🔗

Exothermic reaction

A chemical reaction that transfer thermal energy to the surrounding ♨️

Exothermic Pathway diagram

-> Overall energy change = negative as ebergyis transfer to the surroundings, delta H = - -> y -> energy, x -> progress of reaction -> Every reactants will need to break there bond before a synthesis or decomposition reaction could really happen that part is called Ea thi is where bonds are broken in the substance 📉

Exothermic bond energy

Bonds are formed 🤝

Endothermic reaction

A chemical reaction that absorb thermal energy to the surrounding ❄️

Endothermic Pathway diagram

-> The overall enthalpy change is positive as energy is absorbed as product energy is higher, delta H = + 📈

Endothermic bond energy

Bonds are broken ✂️

Physical Changes

-A change in physical state of a substance that does not involved in chemical reactions + Can separate with physical means + Reversible + No new substances are made -> E.g: Changing state, mixture made, Dissolving substances 🧊

Chemical changes

-Changes which a new substance is formed -> New properties and chemical composition + irreversible + Energy changes 🎇

Concentration of solution

+Increasing the concentration -> More reactant particles in the same volume -> more frequent collisions between reactant particles -> More successful collision -> Increase rate of reaction 💧

Change of gas pressure

Increase in gas preassure More reactant particles in the same volume -> more frequent collisions between reactant particles -> More successful collision -> Increase rate of reaction 🎈

Change of Surface Area

Increase surface area -> More exposed reactent particles -> More frequent collisions -> Increase rate of reaction 🔲

Change in Temperature

Increase in temperature -> Increase in kinetic energy of reactent particles -> More frequent collisions between reactent particles -> increase successful collisions-> Increase in rate of reaction 🌡️

Presence of catalysts

Adding catalyst -> increas reate of reactions by lowering activation energy -> increase reactent particles with sufficient energy for successful collision 🏎️

Collision theory - Rule 1

+ For chemical reaction to happen reactent particles must collide successfully 💥

Collision theory - Rule 2

+ The must be enough energy for collison to be succesfulalso known as Activation energy ⚡

Collision theory - Rule 3

+ The more frequent successful collision the faster the rate of reactions ⏱️