Exam 1 Tuesday 9/29 6:10-8:00 pm CHEM 1650 Bring a non-programmable calculator You will be provided the last two pages of the course pack Practice problems posted on website Exam ethics

Exam Topics Through lab TOMORROW Homework answer key posted Scientific definitions (fact, law, etc.) Scientific method Unit conversions; significant figures Mole Atoms (historical experiments, subatomic particles, size, orbitals, electron configurations) Elements, molecules Periodic table (trends)

Next Chemical Scholarship Assignment Work in new group Presented in Section on Wednesday 10/5 Briefing on chemically modified food Goals –Explore use of chemistry in food –Tie examples to class topics –Determine most controversial and most beneficial

Topics Trans fats MSG Nitrates Homogenized milk Vitamin D in OJ Fluoride in water Fortified flour Iodized salt

Brief What is the modification (chemical structures as appropriate) Why it is done? How it the food modified? What food products does it appear in? Tie in some aspect of this chemistry course (elements, periodic trends, bonding, intermolecular forces, thermochemistry) A brief history (how, when, and where did it all get started?) Is it FDA approved? Summarize the modification advantages and disadvantages Brief us on any debate surrounding the modification (explain the positions that people hold and why they hold them). How heated is the debate? Cite data from at least one scientific study

Misc. 7 minutes total Who’s talking? –Background –Debate –Answers to questions –Questions Power point available

Grading (20 points) 4 points (what, how, where, when) 4 citations including scientific study and results 4 debate 2 tie to chemistry studied in class 2 (1 point each) question answered 2 (1 point each) question asked 2 presentation (volume, clarity, effectiveness)

Exam 2 Tuesday, October 25 6:10-8:00 pm CHEM 1650 Lewis structures; VSEPR Bonding; Polarity Intermolecular forces Thermochemistry –Calorimetry –Phase change –Heats of formation; enthalpy of reactions Aqueous Solutions –concentration units –colorimetry – precipitation

Group Evaluations September (everyone got 9 in-class points) October: – Total points out of total possible*food briefing grade (9/9) –Returned today in discussion Note 75 possible in-class points to date

Exam 2 Range: Mean: 27.5 Median: 28.5

If assigning grades….. Slide down a grade –A 550/700 –B 475/700 –C 400/700 –D 325/700

Intermolecular Forces

Lewis Structures Common answers:

Thermochemistry Heat out of ice –Water 21.3 to 0 o C –Water to ice (heat of fusion) –Ice 0.0 to –22 o C How much propane would you have to burn to get the same amount of heat –C 3 H 8 + 5O 2  3 CO H 2 O –What is  H of reaction? –kJ/mol C 3 H 8 to grams C 3 H 8

Team problem q ice = - q beer q ice = Melt ice + raise temp of water q beer = 6 bottles + ethanol + water