class2 - Class #2 Representations & Composition of...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Class #2 Representations & Composition of Molecules CHEM 107 A. Bengali Texas A&M University Qatar
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
) Numbers of molecules are huge ) Use moles as a unit of quantity ) 1 mole = 6.022 x 10 23 (“Avogadro’s Number”) ) This is an experimentally measured number
Background image of page 2
Avogadro’s Number ) Defined by setting 1 mole 12 C = 12 g ) Definition of the amu is 1 atom 12 C = 12 amu ) Mass of an atom or molecule in amu is numerically equal to mass of one mole in grams
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
mass, moles, # of molecules, . .. ) Converting between these is just changing units. ) Use atomic & molecular weights, densities, etc. as needed.
Background image of page 4
Simple Mole Calculation ) An aluminum bicycle frame weighs about 2.7 pounds. ) How many moles of aluminum is that?
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Mole Problem 2.7 lbs Al = ? Moles Al ) What do we know? atomic wt. of Al = 27, so: 27 g Al = 1mol of Al ± Now just convert units! lbs g moles
Background image of page 6
Mole Problem 2.7 lbs Al = ? Moles Al 1 mole Al = 27 g Al 1 pound = 454 g 2 .7 lbs Al x 454 g 1 l b x 1mole Al 27 g = 45.4 mol Al
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Representing Molecules ) Names : ethanol, ethyl alcohol ) formulas C 2 H 6 O, C 2 H 5 OH, CH 3 CH 2 OH ) structural drawings ) models
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 21

class2 - Class #2 Representations & Composition of...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online