Under standard conditions (298 K and 1 atm), which statement is true?
a] diamond converts to graphite spontaneously
b] graphite converts to diamond spontaneously
c] none of the above
How can the spontaneity of the reaction be reversed? a] increase the temperature
b] decrease the temperature
c] none of the above
If i calculated it right i got Delta H to be -1.9 kJ/mol
Delta S to be 3.3 J/mol k
and Delta G to be -2.9 kJ/mol
does this mean that the first part was a] diamond converts to graphite spontaneously since delta G was negative?
Part 1 is A
Part 2 is C none of the above
Yes, that's exactly what it means. So how do diamonds hold their value? Because
a) most people don't know that.
b) it says nothing about the rate of the reaction. As it happens the activation energy for the reaction C(diamond) ==> C(graphite) is a large bump to get over and it takes a few million years (I didn't calculate late; it's just a number I pulled out of a hat) for diamonds to change back to graphite.
Well, well, well, looks like we got ourselves a thermodynamics question! Let's break it down, shall we?
Under standard conditions, at 298 K and 1 atm, the statement "a] diamond converts to graphite spontaneously" is actually true. Spontaneous means it occurs without any external influence, and diamond converting to graphite is indeed a naturally occurring process.
Now, how to reverse the spontaneity of the reaction? We have two options here: a] increase the temperature or b] decrease the temperature. By changing the temperature, we can shift the balance between diamond and graphite, making the reaction go in the opposite direction. So the answer is neither "none of the above," but rather one of these temperature adjustments.
Now, onto the calculations! With delta H = -1.9 kJ/mol, delta S = 3.3 J/mol K, and delta G = -2.9 kJ/mol, we can conclude that the statement "a] diamond converts to graphite spontaneously" is indeed true. A negative delta G indicates that the reaction is thermodynamically favorable, meaning it will occur spontaneously.
Great job on the calculations! Keep up the good work, my friend!
Under standard conditions (298 K and 1 atm), the conversion between diamond and graphite is not spontaneous. This means that statement a] is not true.
To determine the spontaneity of a reaction, you can use the Gibbs free energy change (ΔG). If ΔG is negative, the reaction is spontaneous, whereas if ΔG is positive, the reaction is non-spontaneous. In this case, you have calculated ΔG to be -2.9 kJ/mol, which is negative. Therefore, the reaction is spontaneous.
To reverse the spontaneity of the reaction, you need to change the conditions. One way to do this is by changing the temperature. To reverse the spontaneity, you should decrease the temperature. So, option b] decrease the temperature is correct.
In conclusion, based on your calculated values, the first statement should be c] none of the above, as the conversion from diamond to graphite is not spontaneous under standard conditions.