1. Combustion Lab Today’s assignment

2. Yesterday’s homework  You calculated answers to # 1-5 on p 205  HW check  Discuss your answers with your partner and once you agree, type your answers to #5 into the class data table on the next slide  We will review the class data  Will we use the average or the median?  Use the class data to answer the analysis questions 1-5

3. Period 4 Answers to #5 a, 5b Ini tial s MP JG LB DP KH RP SM GT MJ AV SY BA MD DP M FH A MB N DT J/k g 617 40 1535 6.25 3906 0 343008593.235,00027,9 30 330 62. 4 399 00 39, 501 kJ/ kg 61.7 40 15.3 5625 39.0 6 34.38.63527.9 3 33. 06 39.939. 501 Class averages: Heat of combustion of paraffin 36205 J/g 36.2 kJ/g

4. Period 7 Answers to #5 a, 5b Ini tia ls ZO MX CT VT TSAH SK SL KO GK AN NK S W VV RR MF N M CM MH CG JR DH J/k g 280 0 26 04 0 24 36 0 23 87 2 24 36 0 30 51 1.7 6 21 62 1.6 13 86 0 31 08 0 15 75 0 kJ/ kg 2826.0 4 24. 36 23. 87 2 24. 36 30. 51 21. 62 16 13. 86 31. 08 15. 75 17. 28 5 Class averages: Heat of combustion of paraffin J/g 24 kJ/g

5. How to answer analysis q #2?  Molar mass of paraffin 352 g / mole  Use that info to convert the experimental number  Convert from kJ / g to kJ/ mol  Start with the experimental number in kJ/g and use the molar mass to convert  Try it, you’ve practiced this skill before

6. Trends in the heat of combustion data table on p. 205 in book

7. Answer the rest of the analysis questions  Write a concluding paragraph  Did you accomplish the purpose of the lab? Restate it to help explain  Summarize the analysis in 2-3 sentences  Refer to your data  Discuss sources of errors  Suggestions for improvements to the lab, procedure  All due in lab books at beginning of next class