Cuprous Sulfate: A Disagreement with My High School Chemistry Teacher

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cuprous sulfate

As a kid, I was excessively shy and retiring – except when it came to matters of science and math. When it came to them, I was generally quiet but I could become quite outspoken if the occasion arose.

During senior year, I approached my math instructor and told him an entire chapter in our textbook was wrong. He was reluctant to hear me out, but when he did, he acknowledged I was correct.

On one occasion during junior year, I was listening to my chemistry teacher attentively when he spoke of cuprous sulfate. For those who are unacquainted with terminology, this would have been the old name (the name I still use) for copper(I) sulfate. I informed Mr. D’Alesandro that the only existing copper sulfate was cupric sulfate, CuSO4, not cuprous sulfate, Cu2SO4. Cuprous sulfate didn’t exist.

Was I correct? Mr. D’Alesandro told me he’d tell me more in class the next day.

Cuprous Sulfate: My Comeuppance

And he did. Although one can make cupric sulfate pentahydrate by the simple combination of copper, sulfuric acid, and water,

cuprous sulfate
Cupric sulfate pentahydrate. Image by Crystal Titan CCA-SA4.0 International

Cu + H2SO4 + 5 H2O → CuSO4•5H2O + H2

the reaction he wrote on the blackboard was,

Cu2O + (CH3)2SO4 → (CH3)2O + Cu2SO4

This reaction reads: cuprous oxide plus dimethylsulfate yields dimethylether plus cuprous sulfate. Admittedly an obscure reaction, still I had been wrong. And what was worse, I had questioned his capability as an instructor although that was not my intent nor did he accuse me of it. I felt pretty foolish. I acknowledged what he said. We never discussed the matter again.

But just how wrong was I?

Acids, Bases, and Salts

First, this was an introductory chemistry course. The chemistry knowledge I had was all gained through my own effort. Then, too, cuprous sulfate is a most unusual compound of limited use, most unusual. Although it can be stored in an anhydrous condition, it is not stable in the presence of moisture or of heat. You are quite unlikely to find it on any laboratory shelf!

Regretting the Outcome

Sadly, my instructor was informed he would not be given tenure. He was, in effect, fired. When I found this out, I felt SO guilty, thinking I might somehow have contributed to his departure. I often wonder whatever became of this fellow. Likely he went to a less demanding school. But I still do not know. Maybe I never will.

Note: You might also enjoy Parametric Equations: I Corrected the Text Book

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2 thoughts on “Cuprous Sulfate: A Disagreement with My High School Chemistry Teacher

  • Challenging (politely) or questioning the information shows that the student is not only listening but THINKING about the content. Any teacher worth the name should welcome student interaction with the material and I see you never forgot the diffrerence between cuprous and cupric! LOL

    • You are correct, Meg. Even so, I am so sorry my teacher was not given tenure. He was a true gentleman and was kind-hearted. One day he even had me substitute for him for a while when he was called away. Me, the ingrate. I would really like to know whatever became of him…

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