 Welcome back MechanicalEI, did you know that reactive systems help us describe every possible reaction in the known universe? This makes us wonder, what are reactive systems? Before we jump in, check on the previous part of the series to learn about what adiabatic flame temperature is. Now, reactive systems basically are the thermodynamic systems that may undergo a chemical reaction. Every chemical reaction is associated a chemical equation which is obtained by balancing the atoms of both reactants and products. Reactive systems make use of these equations to study the thermodynamics of these mixtures. For example, the reaction between the reactants hydrogen and oxygen to form the product water can be expressed as H2 plus half O2 in equilibrium with H2O. This equation indicates that one mole of hydrogen and half a mole of oxygen combine to form one mole of water. The reaction can also proceed in the reverse direction and hence the equilibrium sign. The coefficient one half and one are called stoichiometric coefficients. Hence we first saw what reactive systems are and then saw an example of it. Also thanks a lot for those constructive comments, you helped the channel grow. So here are the top mechanical EIs of our last videos. In the next episode of Mechanical EI, find out what moment of inertia are.