The Periodic Table

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7:36 AM

Q: Comprehensive list of metal alloys along with Moh's hardness scale

Material property lists, such as springermaterials.com, has lists of metal alloys and their properties. Is there a similar website that lists alloys along with their Mohs scale hardness? For springermaterials I can't seem specifically find hardness values. For example, when I search "hardness" or "...

16 hours later…

Hot nitric acid (HNQ)

11:52 PM

Q: Are there separate quantity symbols for the pKa of a substance and the pKa of its conjugate acid?

For polyprotic acids, we distinguish the different deprotonation equilibria and their equilibrium constants by indices, e.g. phosphoric acid dissociation is described by $K_1$, $K_2$, and $K_3$. Considering the acid/base properties of water, there are two relevant equilibria (protonating or depro...