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46 views

Reaction of sulphur with calcium carbonate

Can sulphur react with calcium carbonate to form sulphur trioxide and calcium carbide, as the energy of 3(S=O) is greater than ((C=O) +2(C-O))? EDIT: i forgot to say that this is in an oxygen-free ...
0
votes
1answer
32 views

Calculating bond dissociation enthalpy of F-F bond

$$\ce{N2 + 3 F2 -> 2 NF3} \quad ΔH = \pu{-263 kJ mol-1}$$ The bond dissociation enthalpies of the nitrogen triple bond and nitrogen–flourine bond are $\pu{946 kJ mol-1}$ and $\pu{272 kJ mol-1}....
2
votes
2answers
50 views

I can't find reaction enthalpy ∆H for water formation reaction

$$\ce{1/2 O2(g) + H2(g) → H2O (l)}$$ The tabulated value is $\Delta H = \pu{−285.8 kJ/mol}$ I'm using the bond energies values for each molecule and for some reason, I am getting a different result, ...
2
votes
1answer
38 views

Iron(III) nitrate and hydrogen peroxide reaction

When iron(III) nitrate is added to hydrogen peroxide as a catalyst, the temperature initially decreases and begins to increase after 30 seconds. Why is this the case? (is there any intermediate ...
0
votes
0answers
20 views

why is white phosphorous given to have ZERO standard heat of formation [duplicate]

why is white phosphorous given to have ZERO standard heat of formation?? while it is well known fact that white phosphorous is highly reactive and is obviously less stable than red and black ...
5
votes
1answer
129 views

Using thermodynamics to predict the acid-base character of fluoride ion in water

I was working through the end-of-chapter exercises of the acid-base chapter in Shriver's Inorganic Chemistry when I came across the following problem: 4.7. The effective proton affinity $\ce{A^{'}_{...
0
votes
1answer
43 views

Oxidation of glucose

By oxidation of 9 g of glucose it is released 150 kJ of heat. Calculate the standard enthalpy of derivation of glucose (in kJ/mol), if the given enthalpies of the reactants are ΔfH (H2O(l)) = -285,8 ...
1
vote
0answers
110 views

Anomalous trend in formation enthalpy of alkali metal halides

I read that in alkali metal halides, the formation enthalpy for fluorides become less negative as we go down the group, whereas the reverse is true for chlorides, bromides and iodides. Why is it so? ...
-5
votes
1answer
64 views

Enthalpy of reaction [closed]

Please someone help me with this question How is d possible?
3
votes
1answer
1k views

Why does the energy required to break a bond decrease as the number of bonds increase?

I noticed that the energy to break a single C bond is $348\ \mathrm{kJ}$, to break a double C bond would be $612\ \mathrm{kJ}$, and to break a triple C bond would be $837\ \mathrm{kJ}$. How come the ...
2
votes
2answers
3k views

Is the reaction of silver nitrate and copper endothermic or exothermic?

Is the following reaction endothermic or exothermic and why? $$\ce{2 AgNO3 + Cu -> Cu(NO3)2 + 2 Ag}$$ EDIT: I have a feeling that it is exothermic due to the fact that it is spontaneous and will ...
4
votes
0answers
2k views

Theoretical temperature change in lime hydration

Calcium oxide (quicklime) and water have an exothermic reaction $\ce{CaO + H2O \rightarrow Ca(OH)_2} \quad \quad \Delta H^{\circ}_f=-65.3 \; \mathrm{kJ \cdot mol^{-1}}$ Assume that I have 1 kg of ...
2
votes
1answer
2k views

Stability of beryllium carbonate

Beryllium carbonate is reported to be unstable under normal conditions and should only be kept in a atmosphere of $\ce{CO2}$. Why and how this stability is maintained? Why does this compound decompose ...
7
votes
2answers
249 views

Can negative (abnormally) lattice enthalpies during the formation of ionic compounds exist?

Why do compounds form bonds? I've got three words for you: Less potential energy. I don't remember a case of positive lattice enthalpies $\ldots$ - My comment This makes me wonder. I remember seeing $...