Sunday

April 19, 2015

April 19, 2015

Posted by **Kate** on Saturday, July 3, 2010 at 2:55pm.

My book shows me this diagram instead of just providing a simple formulas that makes no sense at all

here is what I have made sense of so far

(6.022 x 10^23 atoms/mol)(mass of element) = molecular mass

were molecular mass is just the mass number off the periodic table with units g/mol

solving for mass of element will provide the units of g/atoms which makes perfect sense so I think I have this part down if you want to be gramtically correct g/atom

Here's a sample problem in which I would use this equation: Calculate the mass in grams of a single carbon-12 atom

(12.0 g/mol)/(6.022 x 10^23 atoms/mol) = 1.993 x 10^-23 g/atom

Also

(molecular mass)n = mass of element

were mass is the mass of the element given in g and molecular mass is the mass number from periodic table with units g/mol

n is the number of moles

solving for n provides moles for the final unit so I think I get this equation down

Example probelm: How many moles of He atoms are in 6.46 g?

(6.46 g)/(4.003 g/mol) = 1.61 mol

I'm trying to solv this problem

How mnay molecules of ethane C2H6 are present in .334 g of C2H6?

Now I don't now how to solve the problem I posted above were its asking me for molecules

Can someone just show me the apropriate formulas as I'm just reading this crazy diagram and trying to make sense of it and deriving the formulas from it myself... thanks

- Chemistry -
**DrBob222**, Saturday, July 3, 2010 at 4:11pmOK.

You are correct that

moles = grams/molar mass

AND

atomic mass in grams/6.022 x 10^23 = mass of one atom.

# molecules in 0.334 g ethane.

Convert to moles.

moles = grams/molar mass.

0.334/30 = ?? I estimated the 30; you need to confirm it and change if appropriate.

We know 1 mole of anything contains 6.022 x 10^23 molecules; therefore,

# molecules = 6.022 x 10^23 molecules/mole x ??moles from above = # molecules.

By the way, I notice throughout the post that you are omitting an h in**WHERE**which made it a little difficult to understand when I first read it as WERE.

Algebra - What does it mean to be "simplified" which one is most "simple" 2(3+5...

Math - Eighteen students in a class play baseball. Seventeen students in the ...

Chemistry 1 - I have trouble understanding ratios and relativity so I can't ...

statistics - Please Help! My book and instructor are no help. Please help me ...

probability and statistics. - So here I am trying to do my prob/stat homework ...

Math - I am having trouble understanding how to reduce fractions to its lowest ...

sra JMcGuin spanish - Hi I went thru the review packet - I would also have to ...

math - what makes the use of variables diffcult to understand? what makes them ...

6th grade - What is a letter to the editor? I'm doing a book report, but all I ...

Chemistry Help - The orbital diagram shown here has some mistakes in it. ...