I need some help with these. I\'m struggling to understand how to determine posi

Question

I need some help with these. I'm struggling to understand how to determine positive and negative delta g, s, and h and what those mean as far as the state of whatever atom or molecule I am working with (i.e. whether it's solid, liquid, gas, etc.)

. Can water burn at 298 K? 2H,O (l) 02(g) 2 H,02 (1) + Gf -237.192 0.00 120.4 kJmol 4. Predict the sign of AS for the following reactions NaCl (s) a) b) 2 Na (s) + Cl2 (g)-> Cs, (s)-> CS2 (g) 5. For the ammonia synthesis at 25 C, calculate the Change in Gibbs Free Energy if one mole of N (g) at 0.23 bar and 3 mol of H,(g) at 0.42 bar are converted to 2 moles of NH, (g) at 1.45 bar. 6. Is this reaction predicted to favor the produets at low temperature, at high temperatures, or both? Explain your answer Mg(s) (1/2)2 (g) MgO (s) 4"--601.70 kJ + >

Explanation / Answer

delta s is nothing but change in entropy i.e change in randomness.If a molecule is more free to move, it will have high entropy. So, gases will have more entropy as their molecules are more free to move as compare to liquid and same goes with liquid and solid. hence, que4(a) a solid and gas is converting into solid. therefore entropy of the system is decreasing. so delta s will be negative.

In 4(b) solid is convering into gas and because gases have higher entopy than solids, delta s in this case will be positive

delta g deals with free energy of the system. for a reaction to occur, its free energy must decrease. therefore delta g will always be negative if a reaction is happening.

delta h gives us information whether the reaction takes or liberates heat. if it liberates heat than delta h will be negative and if it is consuming heat then it will be positive

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