Test Question

Science questions not covered in Chem 14A and 14B. Try to limit questions to chemistry (inorganic chemistry, physical chemistry, organic chemistry, biophysical chemistry, biochemistry, materials science, environmental chemistry).

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Test Question

Postby JohnWalkiewicz2J » Tue Oct 08, 2019 7:34 pm

Some problems in the textbook give the names of the compounds but not the molecular formulas, for instance: "..a vigorous reaction takes place, and elemental molten barium and solid aluminum oxide are formed." Are we expected to know the formulas for compounds like aluminum oxide? or just common polyatomic ions?

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Re: Test Question

Postby Chem_Mod » Tue Oct 08, 2019 9:30 pm

Formulas will typically be given on the test if they have never been mentioned before, and for simpler compounds, you should be able to figure them out. It is definitely useful to have the common polyatomic ions memorized.

Kallista McCarty 1C
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Re: Test Question

Postby Kallista McCarty 1C » Tue Oct 08, 2019 10:03 pm

The only formula that you must know would be for a combustion reaction. They will give you one of the reactants but you should know it reacts with O2 to produce CO2 and H2O.

Pegah Nasseri 1K
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Re: Test Question

Postby Pegah Nasseri 1K » Tue Oct 08, 2019 10:13 pm

You should be able to write out the molecular formulas of common compounds like aluminum oxide or sodium chloride using the number of valence electrons each atom has. In an ionic compound, you can figure out how many valence electrons each element needs to fill their valence electron shell and balance the charges of each element to find the molecular formula. Having the polyatomic ions memorized will help you with writing some of the molecular formulas that contain them because you will have the charges of each one memorized.

Leslie Magana 4C
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Re: Test Question

Postby Leslie Magana 4C » Tue Oct 08, 2019 10:16 pm

You have to know the combustion reaction according to one of the TAs.

Patricia Chan 1C
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Re: Test Question

Postby Patricia Chan 1C » Wed Oct 09, 2019 12:01 am

You'll need to know combustion reaction reactants and products. Other than that, our TA mentioned that any other molecular formulas that may be more complex are usually given to you on the test. That being said, it might be a good idea to eventually memorize polyatomic ions and understand how to form molecular formulas.

Matt Sanruk 2H
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Re: Test Question

Postby Matt Sanruk 2H » Wed Oct 09, 2019 12:12 am

Any numerical value/constants will be given to us, correct?

Celena Kim 2I
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Re: Test Question

Postby Celena Kim 2I » Sun Oct 20, 2019 5:17 pm

Do we have to recognize charges of certain elements?

Rosa Munoz 2E
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Re: Test Question

Postby Rosa Munoz 2E » Sun Nov 03, 2019 10:36 pm

Matt Sanruk 4F wrote:Any numerical value/constants will be given to us, correct?

The equation sheet we are given for the test is on the website.

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