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P+ = 1234, N= 1111, e- = 1234

P+ = 1234, N= 1111, e- = 1234 . How many jelly beans? How much stuff in you?. What are we made of?. Discrepancy between mass & percentage – lets look at why . All will start to take notes All must be able to calculate molar mass

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P+ = 1234, N= 1111, e- = 1234

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  1. P+ = 1234, N= 1111, e- = 1234

  2. How many jelly beans? How much stuff in you?

  3. What are we made of? Discrepancy between mass & percentage – lets look at why

  4. All will start to take notes All must be able to calculate molar mass All will be able to use Avogadro constant to calculate the amount of atoms and molecules Objectives

  5. YOUR NOTES .... • Your notes – need to reflect your learning • Draw or write or combination • Key points/themes or lots of notes • Try various methods to develop your own style through the next sessions

  6. YOUR NOTES .... • But they should .... • Active listening (listening then reinterpreting for your own notes helps learning) • Follow up with the text books to fill in/make sure you haven’t misunderstood • If you miss one lesson – find & copy/make some from a friend or teacher • If muddled then ask your teacher

  7. Relative atomic mass (Ar) – relative to C 12 H = 1 C 4Be = 2O = 1S Ca=?=? A z Relative atomic mass (Ar)usually measured in grams (g)

  8. Penny sweets .... • H = 1g • C = 12g • O = 16g • S = 32g • So despite weighing differently still cost 1p because ONE SWEET • Only 1 amount; this called 1 MOLE (or mol) • 1 jelly bean • = 1 white mouse • = 1 flying saucer • = 1 fizzy cola bottle

  9. Molar mass is the mass from the periodic table, gmol-1 • Amount in moles of atoms = Mass in grams Molar mass • Moles (mol)= Mass(g) Mr (gmol-1)

  10. Your turn • What are the molar mass of ..... • Na • O • K • How many moles in ... • 96g Mg • 72g C • 80gAr • 80g Ca • I need to have 2 moles of Nitrogen, how much shall I weigh out? • Write out how much of each element I need for this formulae H2SO4 • How many moles of these molecules a.O2 b.2CaCO3 c. NaCl

  11. Answers • What are the molar mass of ..... • 23g • 16g • 39g • How many moles in ... • 4 mol • 6 mol • 4 mol • 4 mol • 28g • Elements ∴ H = (1x2) 2g S = 32g O = (16x4) 64g H2SO4 • Molecules ∴ a1 b.2 c. 1

  12. What is in 1 mole? • In each mole there are the same number formulae units, a constant called Avogadro Constant (NA) • 6.02 x 1023 = Avogadro Constant (NA) • The units depends on the formulae units i.e 6.02 x 1023 molecules mol-1 (NaCl, CuCl2 etc.) 6.02 x 1023 atoms mol-1 (Cu, Zn etc.)

  13. Explain these differences O 16g, C 12g, H 1g & N 14g

  14. Relative molecular mass = 10p mix • Same as 10p mix that you can different combinations/types of sweet but always 10p • Molecular mass is the mass of a formulae unit • Formulae units – can be either single atoms or molecules or gps of ions eg. • Cu • O2 (diatomic) • H2O• CH4•CuCl2 • Learn these through the course, but generally if together class as 1 unit.

  15. Chemical Formulae You can use the moles to work out the formulae C H Amount - 0.12g of C 0.04g of H Molar mass - 12g 1g Moles - (0.12/12) 0.01 (0.04/1)0.04mol Ratio - (0.01/0.01)1 (0.04/0.01) 4 Empirical Formulae CH4 (methane)

  16. Formulae • Two types • Molecular which is the actual number of different atoms • Empirical which is the simplest ratio of the numbers of different types of atoms • Problems Chemical Ideas 1.1, p5

  17. Making hydrated magnesium sulfate crystals • Measuring sulphuric acid (40cm3) • Weighing magnesium carbonate (~6g) • Filter, fit paper into funnel • Filtrate is then heated to leave ~1/3 of solution • Leave for 1-2 days

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