Moles_and_things_(NXPowerLite) Opp

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Mole Theory Grade 10 Unit 5 100’s of free ppt’s from www.pptpoint.com library
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Moles & Things
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Essential Understandings Define atomic, molecular and formula mass Calculate the molecular/formula mass of a compound Define Avogadro’s constant Define the mole and relate it to mass and molecular mass Calculating empirical formula Calculating molecular formulae Finding the percentage composition
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Pre-test For questions 1 to 5 select from the following: Cl Cl 2 Cl - HCl CCl 4 H + 1. A molecule of chlorine …………… 2. An atom of Chlorine …………… 3. An ion of Chlorine ………… 4. A cation …………… 5. An anion …………… 6. Name an element (other than chlorine) whose molecules consist of two atoms. ………. . 7. How many atoms are there in one molecule of sugar C 12 H 22 O 11 ? 8. How many different atoms are there in one molecule of sugar? 9. What is an isotope?
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Atoms, Atomic Masses and Moles Relative atomic Masses: Chemists use a relative atomic mass scale to compare different atoms. In the old days they chose Hydrogen as the standard because it was the smallest atom, but when they were able to find more accurate results and when scientists recognized that elements often consisted of more than one isotope they decided to settle on one isotope. They chose one which was fairly easy to obtain and one which was a solid, so they chose 12 C and they assigned this an atom mass of 12.00000g in this manner none of the previously assigned atomic masses on the old standard of hydrogen had to change too much. They just became more precise.
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The Avogadro constant, moles and molar masses Since one atom of carbon is 12 times as heavy as one atom of hydrogen, it follows that 12g of carbon contain the same number of atoms as 1g of hydrogen. In also follows that the relative atom mass in grams of all the elements (we obtain this from the data in the Periodic Table) will contain the same number of atoms. Experiments show that this number is 6.0 X 10 23 or 600,000,000,000,000,000,000,000. This number is called the Avogadro constant
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As relative atomic mass in grams of all elements contain 6.0 X 10 23 atoms, chemists call 6.0 X 10 23 atoms of an element 1 mole of atoms. (Symbol mol) Strictly speaking, the mole is defined as the amount of substance which contains the same number of particles as there are in 12.0000g of 12 C Relative Atomic Mass Ar is the mass of an atom of an element compared to 12 C
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When we move from elements to compounds
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This note was uploaded on 11/17/2011 for the course PHYS 121 taught by Professor Burgeson during the Fall '11 term at BYU.

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Moles_and_things_(NXPowerLite) Opp - 100s of free ppts from...

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