CHEMISTRY COMMUNITY

Douglas Dean

I thought this was funny! :D

Douglas Dean

The question asks to name the molecule given. It is a cyclohexene, so it is a hexagon with one double bond, and then it has 4 methyl groups attached. The answer given is 1,5,5,6-tetramethylcyclohexene. Why are the methyls numbered 1,5,5,6 instead of 2,3,4,4? In both cases the double bond is on carbo...

Douglas Dean

4a. When dissolved oxygen in water comes in contact with metal iron, rust is formed by the following reaction: 2Fe(s) + 2H2O(l) + O2(aq) --> 2Fe(OH)2(s) Enaut=+0.840V Two different concentrations of oxygen were dissolved in separate water droplets on an iron surface at 298K. The reactions were allow...

Douglas Dean

B) Ron mispronounces the spell, causing his balloon to expand uncontrollably. The balloon starts at 3.3 L and room temperature (298) but ends up at a whopping 9.2x10^5 L and 333K, forcing the entire class to flee the classroom. Calculate deltaS for Ron's balloon. Assume that Helium in the balloon is...

Douglas Dean

Thanks so much Michael! That makes sense, I was just using deltaH not considering it as a reactant. And for the other question, I'm pretty sure deltaS refers to the summation of the entropy of the products minus the summation of the entropy of the reactants. Thus in this problem, you would do deltaS...

Douglas Dean

Chem_Mod wrote:Hi,
Please post the question in full

Sorry about that!

9. Calculate DeltaGr for the balanced reaction showing the decomposition of mercury (II) oxide at 298K.

HgO(s) --> Hg(l) + O2(g)
DeltaHf in kj/mol: -90.83
S in j/kmol: 70.29 76.02 205.14

Douglas Dean

I understand most of the problem and how to get the right answer, you use deltaG = deltaH - TdeltaS, but how do you know that deltaH ends up being a positive value? The value given is negative, thats why it confuses me. Thanks :D

Douglas Dean

I understand how to calculate the work, since it is reversible work has to be done and you use w=-nRTln(V2/V1). However, how do you know that deltaU is zero? And why is q a positive number instead of being zero since the change in temperature is 0 (isothermal)? Thanks :D 3. If 2 mol of an ideal gas ...

Douglas Dean

What is a reversible isothermal reaction and which equation do we use for it?

Douglas Dean

In the equation F = P x A, or in W = P x A x D, does the A stand for normal area or surface area?

CHEMISTRY COMMUNITY

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