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M9... help!

Posted: Tue Oct 08, 2019 3:20 pm
by ChristianM3F
Hi, I tried completing M9, and with my lack of knowledge behind chemical nomenclature, I searched up the molecular formulas of copper (II) nitrate, sodium hydroxide, and blue copper hydroxide. And I checked the solutions manual, and the equations (and even the molecular formulas used) were completely wrong.
Is this just another error in the solutions manual?
And also, just to confirm, we don't need to memorize the formulas of any chemicals for the test tomorrow, right..?
holy-- chemistry's hard

Re: M9... help!

Posted: Tue Oct 08, 2019 3:31 pm
by Ariel Davydov 1C
Hi! The reason why the equation may look off compared to the actual molecular formulas of the molecules listed is because the answer is the net ionic equation, not the molecular equation. This can be reached by "breaking down" the aqueous, soluble molecules (aka the reactants copper (II) nitrate and sodium hydroxide and the other product produced, sodium nitrate) and canceling out the ions that appear the same amount of times on both sides. This leaves you with one mole of the copper (II) ion plus two moles of hydroxide, yielding solid blue copper hydroxide. Reviewing solubility rules and how to form net ionic equations will help with tackling problems like this.

As for memorizing formulas of chemicals for the test, I'm not entirely sure, but the TA at the Sunday review session in Covel said that Lavelle will typically provide them for us. Good luck!

Re: M9... help!

Posted: Tue Oct 08, 2019 4:41 pm
by ChristianM3F
... as someone who's never taken chemistry, and definitely has never heard of solubility rules and forming net ionic equations, will we need to know this before the test tomorrow? Or will we be tested on it specifically when we've covered (or at least brushed up on) the material in class?

Re: M9... help!

Posted: Tue Oct 08, 2019 4:52 pm
by MMckinney_4H
I really doubt that this will be tested this week as it is not specifically covered in the fundamentals listed. However for the future, since this is something that should've been covered in high school, we will likely encounter it and you should probably learn it.