# Can someone help me with this Hess's Law cycle?Watch

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#1
KHCO3 + HCL ---> KCL + H20 + CO2
MgCO3 + 2HCL ---> MgCl2 + H20 + CO2

I need to use them to find out

MgCl2 + 2KHC03 ---> MgCO3 + 2KCl + H20 + CO2

I just need the cycle thanks
0
14 years ago
#2
(Original post by LondonBoy)
KHCO3 + HCL ---> KCL + H20 + CO2
MgCO3 + 2HCL ---> MgCl2 + H20 + CO2

I need to use them to find out

MgCl2 + 2KHC03 ---> MgCO3 + 2KCl + H20 + CO2

I just need the cycle thanks
What do you mean? I assume you are trying to work out the enthalpy of the last reaction?
If you are just trying to combine the two first equations, then reverse the second equation and double the first equation, then combine the two e.g.

2KHCO3 + 2HCL --> 2KCL + 2H2O + 2CO2
MgCl2 + 2KHCO3 --> 2KCl + H2O + CO2

Cancel them, and you will get the last equation....

If you want the enthalpy of the third rxn, it is (2xH1) - (H2) = (H3)
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