1) A paper published earlier this year by Berens et al., (2020, EST) examined the reduction of 2,4-dinitroanisole (DNAN) one of the new generation of insensitive munitions explosives that has become an environmental problem at many Department of Defense facilities. They report that DNAN forms two isomers, 6-methoxy, 3-nitroaniline (also known as 2-amino-4-nitroanisole) and 4-methoxy, 5-nitroaniline (also known as 4-amino-2-nitroanisole). Please answer the following questions.
⢠Calculate the octanol-water partition coefficient using the atom/fragment contribution method. Note that you need to only do this once because they are structural isomers. (10)
⢠There is no âexperimentalâ pKa values for both isomers. Please estimate their pKa values using the Hammett-Taft model. (15)
⢠A different paper by Li et al., (2013, J. Haz. Materials) examined the oxidation of DNAN by ultrasound and the Fenton reaction. They ran their experiments at a pH of 2.7.
i. Determine the speciation of both compounds at this pH i.e., what fraction is protonated vs. neutral. (10)
ii. Recalculate the octanol-water partition coefficients for both isomers at this pH. What is the principal reason behind any difference in your calculated values given that the isomers have the same calculated Kow? (5)
2) A paper by Rudel et al. (EST 2003, 4543) measured the concentration of various pollutants in indoor air. They report respective average levels of 1560 and 426 ng/M3 for diethyl phthalate (DEP) and di-n-butyl phthalate (DBP), which are both present in most plastics (use Chemspider to get additional data).
⢠If these levels are present in your house and you have a bottle of extra virgin olive oil open to the air at 30o C (its summertime), how much of each compound will be in the oil phase (mol/L)? You can assume Raoultâs Law is obeyed and a respective molecular weight and density for the olive oil of 160 g/mol and 0.9 g/ml. (25)
⢠What is the air-olive oil partition coefficient for these two compounds at 25 C based upon:
o The assumption that Raoultâs Law is obeyed (15)
o Estimated based upon the pp-LFER provided in the book (Table 10.2) and the UFZ database. Is the assumption that Raoultâs Law is obeyed a reasonable one? If not what is the activity coefficient for each compound in olive oil? (20)
Sample Solution
As pointed out in the section on Neuroscience above, gaming and game-based learning appears to be the optimal way to learn. Over the next few years games and gaming will increasingly take a significant role in learning. It is important to separate out Gaming from Gamification. Gamification is basically gaming-lite, whereby students get points, rewards, badges and reach levels as they learn. This is no different from the motivational gold stars or scouting badges used over the last hundred years or so and while it has some positive effects, does not have the significant impact on, or potential for, education that actual games have. The key points about gaming for education are as follows: 1. The increase in Massive Multi-Player Online Role-Playing games has a huge potential for teaching and learning as this allows groups of students to interact. More sophisticated simulation-based games focussing on co-operative and project-based tasks (as opposed to fighting and levelling-up) will become increasingly important. Open-world sandbox games where the players create their own scenarios and goals are particularly rich. 2. Education games will need to have the same production values as commercial games. The impact of one-task one-game educational games (e.g. âpop all the balloons with prime numbersâ) is fast diminishing outside early years education. 3. As Blended Learning becomes more important in the classroom, collateral resources for games will be needed. For example, in the case of How to Train Your Dragon, worksheets, literacy activities, physical experiments etc combined with the online game will have a significant impact. 4. Physical games and paper and pen games (such as the original Dungeons and Dragons) will have as much of a role to play as computer games. 5. Learning game design will become as important for education as playing games. There is a potential opportunity here for game building kits that allow students to create both electronic and physical games. 6. The take up of Virtual Reality in the classroom is likely to be slow due to practical and financial considerations. This may change as the headsets become cheaper, though classroom m>
As pointed out in the section on Neuroscience above, gaming and game-based learning appears to be the optimal way to learn. Over the next few years games and gaming will increasingly take a significant role in learning. It is important to separate out Gaming from Gamification. Gamification is basically gaming-lite, whereby students get points, rewards, badges and reach levels as they learn. This is no different from the motivational gold stars or scouting badges used over the last hundred years or so and while it has some positive effects, does not have the significant impact on, or potential for, education that actual games have. The key points about gaming for education are as follows: 1. The increase in Massive Multi-Player Online Role-Playing games has a huge potential for teaching and learning as this allows groups of students to interact. More sophisticated simulation-based games focussing on co-operative and project-based tasks (as opposed to fighting and levelling-up) will become increasingly important. Open-world sandbox games where the players create their own scenarios and goals are particularly rich. 2. Education games will need to have the same production values as commercial games. The impact of one-task one-game educational games (e.g. âpop all the balloons with prime numbersâ) is fast diminishing outside early years education. 3. As Blended Learning becomes more important in the classroom, collateral resources for games will be needed. For example, in the case of How to Train Your Dragon, worksheets, literacy activities, physical experiments etc combined with the online game will have a significant impact. 4. Physical games and paper and pen games (such as the original Dungeons and Dragons) will have as much of a role to play as computer games. 5. Learning game design will become as important for education as playing games. There is a potential opportunity here for game building kits that allow students to create both electronic and physical games. 6. The take up of Virtual Reality in the classroom is likely to be slow due to practical and financial considerations. This may change as the headsets become cheaper, though classroom m>
