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Homework 5 posted-due Wednesday 21 Feb Exam 1 postponed till Friday 23 Feb Mondays suck.

Homework 5 posted-due Wednesday 21 Feb Exam 1 postponed till Friday 23 Feb Mondays suck. What to expect on Exam 1:. Prefixes and conversions between them Sig fig counting and computing Atomic parts and dimensions Average atomic masses Naming compounds

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Homework 5 posted-due Wednesday 21 Feb Exam 1 postponed till Friday 23 Feb Mondays suck.

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  1. Homework 5 posted-due Wednesday 21 Feb Exam 1 postponed till Friday 23 Feb Mondays suck.

  2. What to expect on Exam 1: • Prefixes and conversions between them • Sig fig counting and computing • Atomic parts and dimensions • Average atomic masses • Naming compounds • Names/symbols of common elements (Know first 4 rows) • Moles level 1,2 Hint for studying: See homework 1-5 and quiz 1 (answers at website)

  3. Harder problems….team efforts with clickers

  4. Share with a friend/team mate: (1 clicker for two team mates)

  5. The gram molecular mass of of ‘crystal meth’) is149.2 g/mol. How many moles of crystal meth are in a typical street `teenth’ = 1/16 of an ounce= 1.80 grams ? (1 mol count=6.0*1023.) • 7.27*1021 • 0.0121 • 82.9 • 2.48*10-22 • My answer isn’t above

  6. B1-Aflatoxin (MW=328.2 g/mol) is a naturally occurring, horribly toxic poison derived from Aspergillus fungi, a common contaminant in corn. It causes cancer in most humans at the staggeringly low exposure level of 1*1017 molecules. What is the equivalent mass of aflatoxin represented by this count ? ( 1 mol count=6.0*1023.) • 3.3*10-8 g • 1.8*10-4 g • 5.47*10-5g • 5.06*10-10g • Not any of above

  7. Micro chip manufacture requires nearly oxygen-free conditions wherein the concentration of O2is at or below 17 pg/L. Given that the atomic mass of O is16g/mol, about how many molecules of O2 /L does this represent ? Note: 1 mol count=6.0*1023 • 5.4*1024 • 3.5*1022 • 3.2*1011 • 5.3*1022

  8. Oxycodone, MW=315.4 g/mol is one of the main opioids taken for pain relief. The prescribed dosage per day is 0.105 g. Addicts often take twice that dosage daily to get high. How many molecules are they ingesting ? • 1.26*1023 • 9.00*1023 • 9*1020 • 4*1020

  9. Moles: part 2body parts (mole ratio) math: the knee bone is connected to the thigh bone….

  10. How many hands ??? 1 6 5 2 3 4 7 9 8 10 11 = 22 hands 2 hands 1 people x 11 people

  11. How many toes connected to the hands (assuming no deformities) ? x 1 person hand 5 hands 5 4 = 50 toes x 10 toes person 3 2 1

  12. Simplest `body’ parts example : mole Mole Octane = C8H18 How many H are in 20 moles of octane ? 20 mols octane * 18 mol H = 360 mol H mol octane

  13. Isohexane has the formula C6H14. How many C moles are present if we have 0.1667 moles of isohexane ? • 0.0277 mol C • 1.00 mol C • 36 mol C • 2.333 mol • None of the above

  14. `body’ parts example 2 : Weight moles first, then mol Mol Octane = C8H18 How many moles of octane contain 24 grams of C (at. wt. = 12 g/mol) Step 1) Convert grams C to moles C (all roads lead through moles divide up) 24 g = 2 moles C 12 g/mol C

  15. `body’ parts example 2 : (continued) Octane = C8H18 How many moles of octane contain 24 grams of C (at. wt. = 12 g/mol) Step 2) 2 moles C => how many moles octane? (body parts relationship ?) 1 mol octane=x 8 mol C 2 x= 2/8=0.25 moles octane

  16. Isohexane has the formula C6H14. How many moles of isohexane are formed with 24 grams of C (1 mol C=12 g) • 0.333 moles isohexane • 2 moles isohexane • 0.1667 moles isohexane • 3 moles isohexane • Stoichiometry blows F. None of the above

  17. `body’ parts example 3 : Weight moles , then mol Mol weight Octane = C8H18 (MW=114) How many grams of H are in 10 grams of Octane ? (1 mole H=1 g H) Step 1) Convert grams octane to moles octane All roads lead through moles; divide up 10 g = 0.0877 mol octane 114 g/mol

  18. `body’ parts example 3 (continued) : Octane = C8H18 (MW=114) How many grams of H are in 10 grams of Octane ? (1 mole H=1 g H) Step 2) Relate moles H to moles octane (body parts relationship ?) 18 mol H= x 1 octane 0.0877 x= 18*0.0877=1.579 mol H

  19. `body’ parts example 3 (continued) : Octane = C8H18 (MW=114) How many grams of H are in 10 grams of Octane ? (1 mole H=1 g H) Step 3) convert moles H to grams H (multiply down) 1.228 mol H * 1 g H/mol=1.228 mol H

  20. Isohexane has the formula C6H14. How many grams of H (at. Wt. = 1 g/mol) are combined in 300 grams of C6H14 (MW=86 g/mol) • 36.84 g H • 1.32 g H • 0.249 g H • 0.020 g H • 48.84 g H

  21. Mole Body Part Calculations level 2: More practice, practice, practice 1)mole to mole: how many moles of O are present in 0.1666 mole of C6 H12O6? 1 mol O 2)mole to mole how many moles of C6H12O6 can be made with 12 mole of O ? 2 moles C6H12O6

  22. Mole Calculations: part 2 (cont.) 3) weight to moles how many moles of C6H12O6 in a sample containing 216 g C ? 3mol 4)moles to weight how many grams of C6H12O6 are formed with 0.2666 mol H? = 4 g

  23. Mole Calculations: part 2 (cont.) 5) moles to molecules how many molecules of O are present in 0.8333 mol of C6 H12O6? =5*1023 6) molecules to moles how many moles of C6 H12O6 are formed from 4.32*1025 atoms of H ? 6 moles

  24. Mole Calculations: part 2 (cont.) 7) mass to molecules: how many moleculesof C6 H12O6form from 84 g of C ? 7 *1023 molecules ofC6H12O6 8) atoms to mass: how many grams of H are combined with 2.4*1024 atoms of O in C6H12O 6 ? 8 grams H

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