Enthalpy of Formation: Calcium vs. Magnesium Carbonate

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In summary, the standard enthalpy and entropy values for the following are TiC (TiNitride), VC (Vanadium Carbide), and VN (Vanadium Nitride).
  • #1
Harmony
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Question Statement:
Would you expect the enthalpy change of formation of calcium carbonate to be higher or lower than that of magnesium carbonate.

What I think:
Calcium has a bigger radius than magnesium, hence I expect the lattice energy of MgCO3 to be greater than the CaCO3.

I suspect that the enthalpy of formation is related to the lattice energy. But as for how I am not sure. Can anyone enlighten me on this question?
 
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  • #2
I checked in my files the enthalpy at 298K:

H°(CaCO3) = -1207126 J/mol
H°(MgCO3) = -1095797 J/mol

You can get other info there:

http://webmineral.com/data/Dolomite.shtml
http://webmineral.com/data/Calcite.shtml

I cannot really answer the question. I don't know what is the decisive aspect.
Your answer is not clear for me. The lattice of the dolomite is shorter indeed, but Mg and Ca also have differences in their lattice: atomic density but also the crystallography.
 
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  • #3
i think the enthalpy of formation is related to bond strength and attraction between atoms in the formation. but i still don't know what u mean exactly by lattice energy
 
  • #4
How might electronegativity be used to explain this. Magnesium has a higher electronegativity than calcium.

Element Electronegativity (pauling scale)

Ca 1.00
Mg 1.31
 
  • #5
yep...well than it has something to do with internal energy of the elements, but how can the heat of formation be indpendant of electronegativity ?
 
  • #6
what is the exact definition of electronegativity ?
 
  • #7
thirst for negative charge
 
  • #8
Yes:

FunkyDwarf said:
thirst for negative charge

we all know that.

But a more formal definition may help. There is maybe a link with the enthalpy of formation ...
 
  • #9
Electronegativity is the pull that a certain atom has to attract another atom...i think u can get a better definition from Wikipedia
i would really be surprised if the heat of formation had nothing to do with electronegativity, but there mayb another factor, there should be another factor actually
 
  • #10
I want to know the standard enthalpy and entropy values for the following:

TiN (Titanium Nitride)
TiC (Titanium Carbide)
VC (Vanadium Carbide)
VN (Vanadium Nitride)
 

1. What is the enthalpy of formation for calcium carbonate?

The enthalpy of formation for calcium carbonate, also known as calcite, is -1206 kJ/mol. This means that energy is released when one mole of calcium carbonate is formed from its constituent elements, calcium and carbon.

2. What is the enthalpy of formation for magnesium carbonate?

The enthalpy of formation for magnesium carbonate, also known as magnesite, is -1097 kJ/mol. This means that energy is released when one mole of magnesium carbonate is formed from its constituent elements, magnesium and carbon.

3. Why is the enthalpy of formation for calcium carbonate more exothermic than magnesium carbonate?

This is because calcium has a lower ionization energy and is therefore more reactive than magnesium. This makes it easier for calcium to form bonds with carbon, releasing more energy in the process.

4. How do the enthalpies of formation for calcium carbonate and magnesium carbonate affect their stability?

Due to their exothermic enthalpies of formation, both calcium carbonate and magnesium carbonate are considered to be thermodynamically stable compounds. This means that they are unlikely to decompose into their constituent elements without the input of additional energy.

5. Can the enthalpy of formation for calcium carbonate and magnesium carbonate be used to predict their physical and chemical properties?

The enthalpy of formation is just one factor that can influence the physical and chemical properties of a compound. Other factors such as atomic structure, intermolecular forces, and bonding also play a role. Therefore, while the enthalpy of formation can provide some information about a compound, it cannot be used to fully predict its properties.

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