Will it go? A delta G calculator

Four reactions are stored with their $\Delta H$ in kJ/mol and $\Delta S$ in J/(K mol). You will write a function for $\Delta G$, use it to find which reactions are spontaneous at a given temperature, and find where one of them turns spontaneous.

The idea. $\Delta G = \Delta H - T\Delta S$, with $\Delta S$ divided by $1000$ so both parts are in kJ/mol. Where $\Delta H$ and $\Delta S$ share a sign, $\Delta G$ is zero at $T = \Delta H / \Delta S$.

Your tasks.

1. Complete delta_g(dh, ds, t) so that it returns $\Delta G$ in kJ/mol.
2. Set spontaneous_at_300 to the list of the names whose $\Delta G$ is negative at $300\ \text{K}$, in the order of the dictionary.
3. Set turning to the temperature in K, rounded to a whole number, where $\Delta G$ of "D" is zero.