When do you assume something is diatomic?

[starsweet]

So obviously I know BrINClHOF, but Kaplan had a question about the number of molecules in 20 g of oxygen gas. I immediately assumed it was diatomic (esp. since it said "oxygen gas") but the explanation used 16 g/mol to convert the 20 g to molecules. Why did they use 16 g/mol and not 32 g/mol?

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[ndearwater]

So obviously I know BrINClHOF, but Kaplan had a question about the number of molecules in 20 g of oxygen gas. I immediately assumed it was diatomic (esp. since it said "oxygen gas") but the explanation used 16 g/mol to convert the 20 g to molecules. Why did they use 16 g/mol and not 32 g/mol?

Kaplan has a lot, and I mean a lot, or errors and typos. This is a serious problem for doing calculations. I honestly believe that in that problem you should use 32g/mol. Oxygen gas is diatomic.
Oxygen

"Oxygen, O2, is a colourless odourless gaseous main group element which belong to Group VIb of the periodic table.
Atomic Number : 8
Atomic Mass : 15.9994
Melting Point : -214 degC
Boiling Point : -183 degC
Density : 1.429"

Just know Brinclhof

 

[PharmEm]

I was doing that EXACT same problem yesterday. I used 32 in my calculations but Kaplan said it was 16. That's one thing I hate about Kaplan, all the typos and calculation errors. I mean, you would think Kaplan could afford someone to look over the book before they publish it. It's just annoying b/c your not sure whether your way is the right way or not! I wonder if other study guides (Barrons, Petersons, Princeton, Exam Crackers, Lippencotts, etc) have the same problem with typos and calculation errors.

 

[starsweet]

No kidding, it's ridiculous! I may write them a nastygram once this test is over...

I just didn't want to get a simple problem like that wrong, so I wanted to make sure I was right in using BrINClHOF.

 

[chuks_pharmD]

hi...even i was doing that one last night.....and i asumed it was diatomic...and guess what i was wrong...

But now that u all have clarified it...i'm genious....

 

[megrxgirl]

Kaplan has a lot, and I mean a lot, or errors and typos. This is a serious problem for doing calculations. I honestly believe that in that problem you should use 32g/mol. Oxygen gas is diatomic.
Oxygen

"Oxygen, O2, is a colourless odourless gaseous main group element which belong to Group VIb of the periodic table.
Atomic Number : 8
Atomic Mass : 15.9994
Melting Point : -214 degC
Boiling Point : -183 degC
Density : 1.429"

Just know Brinclhof

What is Brinclhof??????????

 

[SpOrTsChIc]

Just a way to remember all of the diatomic elements.
BRomine, Iodine, Nitrogen, ChLorine, Hydrogen, Oxygen, Fluorine

What is Brinclhof??????????

 

[megrxgirl]

Just a way to remember all of the diatomic elements.
BRomine, Iodine, Nitrogen, ChLorine, Hydrogen, Oxygen, Fluorine

oh ok....