The preparation of NO2(g) from N2(g) and O2(g) is an endothermic reaction: N2(g)+O2(g) ⟶NO2(g)

The preparation of NO2(g) from N2(g) and O2(g) is an...

The preparation of $\mathrm{NO}_{2}(g)$ from $\mathrm{N}_{2}(g)$ and $\mathrm{O}_{2}(g)$ is an endothermic reaction: $$ \mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{NO}_{2}(g) \text { (unbalanced) } $$ The enthalpy change of reaction for the balanced equation (with lowest whole-number coefficients) is $\Delta H=67.7 \mathrm{~kJ}$. If $2.50 \times$ $10^{2} \mathrm{~mL} \mathrm{~N}_{2}(g)$ at $100 .{ }^{\circ} \mathrm{C}$ and $3.50$ atm and $4.50 \times 10^{2} \mathrm{~mL} \mathrm{O}_{2}(g)$ at $100 .{ }^{\circ} \mathrm{C}$ and $3.50 \mathrm{~atm}$ are mixed, what amount of heat is necessary to synthesize the maximum yield of $\mathrm{NO}_{2}(g)$ ?

The preparation of $\mathrm{NO}_{2}(g)$ from $\mathrm{N}_{2}(g)$ and $\mathrm{O}_{2}(g)$ is an endothermic reaction:
$$
\mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{NO}_{2}(g) \text { (unbalanced) }
$$
The enthalpy change of reaction for the balanced equation (with lowest whole-number coefficients) is $\Delta H=67.7 \mathrm{~kJ}$. If $2.50 \times$ $10^{2} \mathrm{~mL} \mathrm{~N}_{2}(g)$ at $100 .{ }^{\circ} \mathrm{C}$ and $3.50$ atm and $4.50 \times 10^{2} \mathrm{~mL} \mathrm{O}_{2}(g)$
at $100 .{ }^{\circ} \mathrm{C}$ and $3.50 \mathrm{~atm}$ are mixed, what amount of heat is necessary to synthesize the maximum yield of $\mathrm{NO}_{2}(g)$ ?

Key Concepts

Ideal Gas Law

The ideal gas law (PV = nRT) is a fundamental principle that relates the pressure, volume, temperature, and number of moles of a gas. This concept is used to convert the measured volume of gases under specified conditions of pressure and temperature into the number of moles, which is essential for quantitative calculations in gas reactions.

Limiting Reactant

The limiting reactant concept determines which substance in a chemical reaction is present in the smallest stoichiometric amount relative to the balanced equation, thus limiting the extent of the reaction. Identifying the limiting reactant allows chemists to determine the maximum possible yield of products and calculate the associated energy changes.

Stoichiometry

Stoichiometry involves using the balanced chemical equation to relate the moles of reactants to the moles of products. It provides a quantitative basis for calculating how much product can be formed when given specific amounts of reactants and is key to linking mole quantities with energy changes in reactions.

Enthalpy Change (?H)

The enthalpy change of reaction, ?H, represents the amount of heat absorbed or released during a chemical reaction at constant pressure. In the context of an endothermic reaction, it indicates the heat input required per mole of reaction, serving as a critical factor in determining the total energy needed to synthesize the reaction products.

Transcript

00:02 So this question gives us an unbalanced eclosure, and we need to determine the maximum yield of no2.

00:10 So because they give us so much information for both of our reactants, that's what's going to lead us to think that this is a limiting reactive problem.

00:19 So we're going to figure out which of our reactants is limiting first, and then we'll work from our limiting reaction to determine our energy.

00:29 So we need to get some moles of each reactant before we can do anything else.

00:34 And in order to do that, we also need a balanced equation to start with.

00:38 Since it gave us an unbalanced equation, let's just go ahead and balance it out first.

00:43 So we have n2 gas plus o2 gas, making n02 gas.

00:53 So we need two's there in order for it to be a actual valid balanced equation.

01:03 So now we're going to use the ideal gas equation to figure out how many moles of n2 and o2 we have available in order to help us determine which one's limiting.

01:18 So let's get to moles of n2 first.

01:21 So we know that if we're getting moles of n2, that's pv over rt.

01:29 And it gave us information for that.

01:30 We know the pressure was 3 .50 times 0 .250 times our r value times temperature.

01:59 It's going to give us 2 .86 times 10 to the negative 2 moles of n2.

02:09 We're going to do the same thing for the o2 to figure out our moles of o2, but we're going to use the information for the o2 instead...

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