Thursday, November 5, 2015

Molar Mass

We learned how to calculate the molar mass of a compound in class today. I found the concept easy to learn. However, I do need to review my polyatomic ions. 

 This is one example we did in class. We still need to round to the correct number of significant figures in the end.
Magnesium chloride = MgCl2 = 1(24.31) + 2(35.45) = 95.21 g/mol

Mrs. Frankenberg also taught us the diatomic ions. They are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. When these elements are sitting alone, you must double their mass from the periodic table to find their molar mass. 

 For example, O2 = 2(16.00) = 32.00 g/mol

 Below, I posted a picture of the polyatomic ions that I can use to study and a link to practice calculating the molar mass of compounds before the exam. 

http://crescentok.com/staff/jaskew/isr/tigerchem/naming/a85.htm

molar mass quiz
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7 comments:

  1. AnonymousNovember 6, 2015 at 11:18 AM

    Good information! Also thanks for including the polyatomic ions, I really need to study them.

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  2. Emmeline KooNovember 15, 2015 at 8:31 AM

    Thanks for the review over the polyatomic ions and good summary over the days lesson. You should also add your own attempts or practices.

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  3. UnknownNovember 15, 2015 at 6:05 PM

    Thank you for the review of the polyatomics because I forgot some of them for some time as well. This was a really good summary of that day's lesson, and it is an easier concept that is a part of this unit. Thank you for this! I also agree with Emmeline: including a couple examples may help!

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  4. AnonymousNovember 16, 2015 at 8:44 AM

    I would agree with you saying that the concept was easy except if you don't know the polyatomic ions. I had that problem when I was doing some practice problems.

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  5. UnknownNovember 16, 2015 at 2:46 PM

    Great post Lily! I like the picture you used to review polyatomic ions, which are showing up in some of the calculations for molar mass.

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  6. AnonymousNovember 16, 2015 at 8:30 PM

    Thanks for this reminder of the charges for polyatomic ions it helped me on the test today because I used your chart to help me study.

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  7. AnonymousNovember 17, 2015 at 2:33 PM

    Lily, I found your post extremely helpful with the polyatomic ions image. It was a great study item for the test we recently took.

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