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This also describes another common use of per-, perhalogenated compounds. In that context, it usually means that all hydrogens present in the parent compound, that were bonded to a carbon, have been replaced with a halogen, for example perfluoroethylene (C2F4, also known as tetrafluoroethylene, the monomer of Teflon(PTFE))
It is shorthand for molarity. More precisely the amount concentration. It is used as a unit and stands for mole per litre. The IUPAC gold book writes: amount concentration, Amount of a constituent divided by the volume of the mixture.
The -1 means "per" unit. So your first example mol/L-1 /s-1 is not correct - it would actually be written as mol L-1 s-1, OR mol/(L s). It is also sometimes written as mol/L/s, but the double division is ambiguous and should be avoided unless parentheses are used. If it were mol L-1 s-2, this would mean moles per litre per second per second.
It means the hydrogenated version of an aromatic with 4 hydrogens added. Generally used where the hydrogenated version does not have a separate name though there is some crossover e.g. tetrahydronaphthalene/tetralin. To be completely systematic the name should specify which bonds are saturated. e.g. tetralin/1,2,3,4-tetrahydronaphthalene ...
Some will take longer, some will be quicker. Only for a large number of turnovers in aggregate does that time value have meaning. Saying that "a turnover takes 5 s" gives a false impression about individual turnovers in a way that saying "this enzyme works at 0.2 turnovers per second" doesn't.
$\begingroup$ Per-O-acetylated sugars are sugars where each (thus, per) hydroxyl group (thus O) is converted into an ester of HOAc. E.g., scielo.br/… For glucose, for example, to get you glucose pentaacetate. $\endgroup$ –
The per mol arises from the definition of the reaction enthalpy change, $\Delta_\mathrm{r}H^\circ$. I have another answer describing it in the context of Gibbs free energy here. However, one way to look at it is to remember that the reaction does not stipulate the actual amounts of reactants and products.
Molarity is just one way to express concentrations, which, more specifically, is the number of moles of solute per liter of solution. But you can give values for concentrations in many different ways, like for example, grams of solute per liter of solution, percentages (grams of solute divided by the grams of solution multiplied by 100), etc.
Both the prefixes bis-, tris-, tetrakis-etc. and the prefixes di-, tri-, tetra-etc. are used to describe how many times a certain single ligand attaches to a central metal — and this usage is no different here than in typical molecule nomenclature.
It seems that in some cases it's the same (that is, $\Delta Q_p=\Delta H$) yet in others they differ. Heat is an energy transfer, whereas enthalpy is a kind of energy content of a sample.