The major industrial source of hydrogen gas is by the following reaction: CH4(g)+H2 O(g) ⟶CO(g)+

The major industrial source of hydrogen gas is by the...

Key Concepts

Bond Energy

Bond energy is the amount of energy required to break a bond between two atoms in a molecule. In chemical reactions, bonds in the reactants must be broken (an endothermic process) before new bonds form in the products (an exothermic process). Estimating reaction enthalpy using bond energy values involves summing the energies required to break bonds and subtracting the sum of energies released when new bonds form.

Thermochemistry

Thermochemistry is the study of heat and energy changes that accompany chemical reactions. It involves analyzing how energy is absorbed or released during a reaction, which is crucial for understanding reaction spontaneity and feasibility. Bond energy calculations are a common thermochemical method to estimate the overall energy change (enthalpy change) of a reaction.

Enthalpy Change (?H)

Enthalpy change represents the net heat absorbed or released during a chemical reaction at constant pressure. It is determined by the difference between the total energy required to break bonds in the reactants and the total energy released during the formation of bonds in the products. A negative ?H indicates an exothermic reaction, while a positive ?H indicates an endothermic reaction.

Industrial Hydrogen Production (Steam Reforming)

Industrial hydrogen production via steam reforming involves reacting methane with steam to produce hydrogen and carbon monoxide. This process is economically and energetically important, and its feasibility can be evaluated using bond energy calculations to predict whether the reaction is overall endothermic or exothermic. This understanding is critical in optimizing conditions for large-scale hydrogen generation.

Transcript

00:02 Okay, so for this one we're going to be looking at, we're going to be solving for the change in energy.

00:09 And we're going to be looking at this equation right here.

00:12 The one thing i like to do is i like to draw out the structure of these molecules.

00:19 So i can see the actual bonds that are taking place.

00:22 And so we have water bonded to the two hydrogens.

00:27 We have carbon that's going to be triple bonded to oxygen and carbon monoxide.

00:31 And then we have our hydrogen bonded to hydrogen.

00:34 We have three molecules of that.

00:36 The next thing that we have to do is we have to get these, we need to look and see how much energy, the bond energy that there is found in between these different bonds.

00:47 So we have carbon and hydrogen bond.

00:49 We have oxygen bonded to hydrogen over here.

00:52 We have carbon triple bonded to oxygen, and then we have our hydrogen bonded to another hydrogen.

00:59 So we need to get these values.

01:01 You can just get these values off the internet or whatever.

01:04 So carbon bonded to hydrogen is 413 kilojoules per mole.

01:12 Oxygen to hydrogen is 467 kilojoules per mole.

01:20 And then we have this big old sucker.

01:22 This is a lot of bonding energy found in that bond because it's triple bonded, obviously.

01:27 Then we have our hydrogen, hydrogen, which is 432.

01:30 2.

01:32 And so using these values, we can then calculate the change in energy.