Solve Hess's Law Equation 4: HCl + NH3 --> NH4Cl

[needphyshelp]

Homework Statement

Manipulate equations 1-3 to show the formation of the overall equation 4.
Equation 4: HCl + NH₃ --> NH₄Cl

Homework Equations

1. NaOH + HCl --> NaCl + H₂O
2. CH₃CO₂H + NaOH --> CH₃CO₂^- +Na⁺ + H₂O
3. CH₃CO₂H + NH₃ --> CH₃CO₂^- +NH₄⁺

The Attempt at a Solution

I kept equation 1 and 3 the same, reversed equation 2 and summed them. My result is HCl + Na + NH₃ --> NaCl +NH₄.

I have no idea how to get to equation 4 from here...

 

[nate808]

To derive equation 4 from equations 1-3, we can start by combining equations 1 and 2. This will give us NaOH + CH3CO2H --> NaCl + CH3CO2- + H2O.

Next, we can substitute NaOH with NH3 in equation 2 to get CH3CO2H + NH3 --> CH3CO2- + NH4+ + H2O.

Finally, we can combine this equation with equation 3 to get CH3CO2H + NH3 + CH3CO2H --> CH3CO2- + NH4+ + CH3CO2- + H2O.

Simplifying this equation, we get HCl + NH3 --> NH4Cl as desired.

I hope this helps! Let me know if you have any further questions. Keep up the good work in your studies.

 

[Blueshift5]

I would like to clarify that Hess's Law is not an equation, but rather a principle that states that the enthalpy change of a reaction is independent of the pathway taken. In other words, the overall enthalpy change of a reaction can be calculated by summing the enthalpy changes of individual reactions that make up the overall reaction. Therefore, to solve for equation 4, we can use Hess's Law to manipulate equations 1-3.

First, let's take a look at the overall reaction: HCl + NH3 --> NH4Cl. We can see that this reaction involves the combination of HCl and NH3 to form NH4Cl. Therefore, we need to find a way to get HCl and NH3 on the reactant side and NH4Cl on the product side.

Looking at equation 1, we see that it involves the reaction of HCl with NaOH to form NaCl and H2O. We can use this equation to get HCl on the reactant side by reversing it: NaCl + H2O --> NaOH + HCl.

Next, we can use equation 3 to get NH3 on the reactant side. By reversing it, we get CH3CO2- + NH4+ --> CH3CO2H + NH3.

Now, we have HCl and NH3 on the reactant side and NH4Cl on the product side, but we also have NaCl and CH3CO2- on the product side. We can use equation 2 to get rid of NaCl by reversing it and summing it with our previous equations: CH3CO2H + NH3 + Na --> CH3CO2- + NH4+ + Na + H2O.

Finally, we can cancel out the Na on both sides and rearrange the equation to get our final result: HCl + NH3 --> NH4Cl.

Therefore, by using Hess's Law and manipulating equations 1-3, we were able to solve for equation 4 and show the formation of NH4Cl.