Dinitrogen monoxide, N2 O, can decompose to nitrogen and oxygen gas: 2 N2 O(g) ⟶2 N2(g)+O2(g),Us

Dinitrogen monoxide, N2 O, can decompose to nitrogen and...

Dinitrogen monoxide, $\mathrm{N}_{2} \mathrm{O},$ can decompose to nitrogen and oxygen gas: $$2 \mathrm{N}_{2} \mathrm{O}(\mathrm{g}) \longrightarrow 2 \mathrm{N}_{2}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g})$$,Use bond energies to estimate the enthalpy change for this reaction.

Key Concepts

Bond Dissociation Energy

Bond dissociation energy represents the amount of energy needed to break a chemical bond in one mole of gaseous molecules. It is a key parameter in understanding the stability of bonds in molecules and is essential in calculating the energy changes during chemical reactions.

Reaction Enthalpy Calculation Using Bond Energies

This concept involves estimating the enthalpy change of a reaction by summing the energies required to break bonds in the reactants and subtracting the energies released upon forming bonds in the products. It provides a way to approximate reaction energetics using average bond strength values.

Thermochemistry

Thermochemistry is the study of heat transfer in chemical reactions. It focuses on understanding and calculating the energy changes that occur, such as those involved in breaking and forming chemical bonds, which enables the prediction of whether reactions are endothermic or exothermic.

Transcript

00:01 In this question, we are calculating the enthalpy of reaction, and the reaction is the decomposition of di -nitrogen dioxide into nitrogen gas and oxygen gas.

00:12 Now, the first step to solving a question like this is to draw out the structures so that you know which bonds you're breaking and which ones you're making.

00:22 So the structure of dinitrogen oxide is nitrogen, triple bond to the other nitrogen.

00:31 Single bonded to the oxygen.

00:35 Now there are other possible resonance structures, but if you check your formal charges, you'll find that this one is the most favorable.

00:43 And we're going to draw it again because there's two of them.

00:54 And that's going to turn into nitrogen gas, which looks like this, and we have two of those two, and oxygen gas, which will look like this.

01:17 So from a lot of an energetic standpoint, we are breaking these bonds, we are making these bonds.

01:28 So let's get to the math part.

01:32 The enthalpy of this reaction is delta h of the reaction is equal to the energy required to break the bonds.

01:46 So that is, i'm just going to say, break, plus the energy.

01:54 Energy associated with making the bonds.

02:00 And different equations from different textbooks will use different signs, but i'll guide you through that in just a moment.

02:08 So let's start with calculating out breaking the bonds.

02:15 First up, we have this nitrogen -nitrogen bond.

02:20 It takes energy to break bonds.

02:24 So, and we know from our table that the nitrogen -nitrogen -nitrogen bond.

02:28 Nitrogen bond has 945 kilojoules, or it'll take that much to either break or form.

02:38 So we have 945, and it's a positive because breaking bonds requires energy.

02:51 Then we also have to break this nitrogen and oxygen bond, and that value is 201 kilojoules.

02:59 And since we have two of them, we're going to multiply this by two.

03:06 Next, we have to make two of these nitrogen gas bonds.

03:12 That's same nitrogen, nitrogen, triple bond...

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