Help me out because I attempted these and realized I did not solve them in KJ/Moles. How do you figure out change of enthalpy with the units kJ/moles?
My two reactions.
First balanced:
MgO (s) + 2 HCl (aq) --> MgCl2 (aq) + H2O (l)
Second balanced:
Mg (s) + 2 HCl (aq) --> MgCl2 (aq) + H2 (l)
I just need the individual delta H for each in KJ/moles.
Let's see, MgO mass: 1.010 g.
HCl mass: 80.376 g.
I also got 0.0251 moles of MgO.
Mg mass: 0.308 g.
HCl mass: 89.961 g.
Back to my original question, if you show how you obtained that 8.39 perhaps I will know where you're going with this. I don't know where you get values for aqueous solutions when you don't know their concentrations. But I do know that the values are zero for Mg solid and H2 gas (but you show liquid). Surely you meant gas.
I'm sorry. I'm quite confused too. Where are you getting 8.39? I have no idea what is going on anymore. This lab got too convoluted for my taste. No worries, thanks for your help anyways.
Three hours ago and an hour later you posted this current post. Your original post is here. https://www.jiskha.com/questions/1852512/help-me-out-because-i-attempted-these-and-realized-i-did-not-solve-them-in-kj-moles-how
That's where I found the 8.39 value I quoted. I asked there about providing information about how you obtained the 8.39 kJ but no response. Then you posted this current saying you don't know anything about that. I'm just trying to find out how and where you obtained that number. Hopefully then I can figure out where you are going with this problem. I can't help if I don't get information.
To calculate the change in enthalpy (ΔH) in kJ/mol for each reaction, you need to use the stoichiometry of the balanced chemical equations and the amount of reactants used.
For the first reaction, MgO (s) + 2 HCl (aq) → MgCl2 (aq) + H2O (l), you have the following information:
- Mass of MgO = 1.010 g
- Moles of MgO = 0.0251 mol (calculated using the molar mass of MgO)
- Moles of HCl used = 0.0251 mol (since the stoichiometric coefficient of HCl is 2)
To calculate the ΔH in kJ/mol, you need to divide the change in heat (ΔH) by the number of moles of the limiting reactant (in this case, MgO). However, since the mass of HCl is given instead of the moles, you need to convert the mass of HCl to moles using its molar mass.
For the second reaction, Mg (s) + 2 HCl (aq) → MgCl2 (aq) + H2 (l), you have the following information:
- Mass of Mg = 0.308 g
- Moles of Mg = 0.308 g / molar mass of Mg (calculating the moles of Mg using its molar mass)
- Moles of HCl used = 0.308 g / molar mass of HCl (calculating the moles of HCl using its molar mass)
Similar to the first reaction, you will divide the change in heat (ΔH) by the number of moles of the limiting reactant (in this case, Mg).
To actually calculate the ΔH for each reaction in kJ/mol, you'll need the additional information about the change in heat (ΔH) or the enthalpy of formation values for each compound involved in the reactions. This information is typically provided in tables or can be looked up in reference sources.
Once you have the enthalpy values, you can use them to calculate the ΔH for each reaction by multiplying the stoichiometric coefficients of the reactants and products by their respective enthalpy values, and then subtracting the sum of the reactant enthalpies from the sum of the product enthalpies.
Unfortunately, without the specific enthalpy values for each compound, it is not possible to provide the exact ΔH values in kJ/mol for the given reactions.