Environmental Chem C

[packer-backer91]

has anyone really been asked any questions on the 12ish types of soils [ie like Alfisols or oxisols to name a few]? Also what are some examples of the dilution or conversion problems others have seen [for me I haven’t seen any this year]

[Phenylethylamine]

has anyone really been asked any questions on the 12ish types of soils [ie like Alfisols or oxisols to name a few]? Also what are some examples of the dilution or conversion problems others have seen [for me I haven’t seen any this year]

In my experience, there's usually at least one question on the USGS soil classification (the alfisols, etc stuff), which makes it worth having a small table of all that on your reference sheet, but not worth attempting to memorize anything about the types.

We didn't have dilution at States, but one of the practice tests on the wiki has a bunch of dilution problems.

Also, we had two questions where the names of two reactants were given, and you had to write the net ionic equation. I remember one was sodium chloride + silver nitrate --> ?, and the other involved ammonia. The former was actually related to the lab (you had to figure out which soil sample "could have been taken from next to a New York City sidewalk in the winter"... infer that the sidewalks are salted- not usually with sodium chloride, actually, but that's beside the point- and then test the samples with silver nitrate to see which formed more white precipitate- silver chloride, which is formed as a product and is insoluble).

[packer-backer91]

In my experience, there's usually at least one question on the USGS soil classification (the alfisols, etc stuff), which makes it worth having a small table of all that on your reference sheet, but not worth attempting to memorize anything about the types.

We didn't have dilution at States, but one of the practice tests on the wiki has a bunch of dilution problems.

Also, we had two questions where the names of two reactants were given, and you had to write the net ionic equation. I remember one was sodium chloride + silver nitrate --> ?, and the other involved ammonia. The former was actually related to the lab (you had to figure out which soil sample "could have been taken from next to a New York City sidewalk in the winter"... infer that the sidewalks are salted- not usually with sodium chloride, actually, but that's beside the point- and then test the samples with silver nitrate to see which formed more white precipitate- silver chloride, which is formed as a product and is insoluble).

your chem problem the way you say it they wanted you to do a reaction between them: NaCl + AgNO(3) -> NaNO(3) + AgCl. For the net ionic equation is the charges for each, that’s basic chem stuff, that was what half of my env chem test was last year at state was balance equations and reactions.

[Phenylethylamine]

Also, we had two questions where the names of two reactants were given, and you had to write the net ionic equation. I remember one was sodium chloride + silver nitrate --> ?, and the other involved ammonia. The former was actually related to the lab (you had to figure out which soil sample "could have been taken from next to a New York City sidewalk in the winter"... infer that the sidewalks are salted- not usually with sodium chloride, actually, but that's beside the point- and then test the samples with silver nitrate to see which formed more white precipitate- silver chloride, which is formed as a product and is insoluble).

your chem problem the way you say it they wanted you to do a reaction between them: NaCl + AgNO(3) -> NaNO(3) + AgCl. For the net ionic equation is the charges for each, that’s basic chem stuff, that was what half of my env chem test was last year at state was balance equations and reactions.

Exactly, I was offering that as an example of a type of question that's likely to show up (not asking for help with it, although thank you). Actually, for the net ionic equation, you have to write out the dissociated ions of all the aqueous products and reactants (solids, liquids and gases remain in their unionized forms), and then leave out "spectator ions" (any ion that appears on both sides of the equation). The remaining equation is your net ionic equation. For example:

NaCl(aq) + AgNO3(aq) --> NaNO3(aq) + AgCl(s)

Na+(aq) + Cl-(aq) + Ag+(aq) + NO3-(aq) --> Na+(aq) + NO3-(aq) + AgCl(s)
Na+ and NO3- appear on both sides of the equation, so we leave them out:

Ag+(aq) + Cl-(aq) --> AgCl(s)
This is your net ionic equation.

[packer-backer91]

Exactly, I was offering that as an example of a type of question that's likely to show up (not asking for help with it, although thank you). Actually, for the net ionic equation, you have to write out the dissociated ions of all the aqueous products and reactants (solids, liquids and gases remain in their unionized forms), and then leave out "spectator ions" (any ion that appears on both sides of the equation). The remaining equation is your net ionic equation. For example:

NaCl(aq) + AgNO3(aq) --> NaNO3(aq) + AgCl(s)

Na+(aq) + Cl-(aq) + Ag+(aq) + NO3-(aq) --> Na+(aq) + NO3-(aq) + AgCl(s)


Na+ and NO3- appear on both sides of the equation, so we leave them out:

Ag+(aq) + Cl-(aq) --> AgCl(s)
This is your net ionic equation.

I didn't know what your question was asking, last year the test was mostly balance the reaction with adding charges and phase notation. Then they made you sometime diagram out what the molecule looks like [dot diagram]. They never gave me a problem like your example that will be another chem problem to practice with. They used exactly half of test to ask general chem equations that some how they thought relates to env chem. The other half of test was a soil sample experiments and relate that work to how to make the soil better for growing crops. This event in the rules don’t have a limited on the questions they can ask. Yes they say that they should relate to the soil chemistry in the event but they really don’t have much relevance for what the rules intended.

[Phenylethylamine]

I didn't know what your question was asking, last year the test was mostly balance the reaction with adding charges and phase notation. Then they made you sometime diagram out what the molecule looks like [dot diagram]. They never gave me a problem like your example that will be another chem problem to practice with. They used exactly half of test to ask general chem equations that some how they thought relates to env chem. The other half of test was a soil sample experiments and relate that work to how to make the soil better for growing crops. This event in the rules don’t have a limited on the questions they can ask. Yes they say that they should relate to the soil chemistry in the event but they really don’t have much relevance for what the rules intended.

Yeah, it's not uncommon for events to be heavy on the "Chem" and light on the "Environmental". Last year's B Division national event was a good balance, though. I think this problem- or just property, depending on how you see it- is mainly at the state level, although NY States this year was pretty good.

[peoneill]

I beat the students senseless with the USGS classifications at the Indiana tournament this year. I mean, one of the 8 topics for the event is soil classification... and that's the dominant system for doing it. But most teams were unable to answer even the simplest questions about USGS!

Most of the E Chem coordinators don't really seem to know much E chem, to be blunt. I don't know where all the environmental chemists are, but not volunteering for SO, apparently. I've seen last year's national exam and I found it to be pretty trivial. Hopefully if it is the same coordinator he or she has had a full year more experience engaging with the event and can pull out some more sophisticated science.

[kjhsscioly]

I didn't know what your question was asking, last year the test was mostly balance the reaction with adding charges and phase notation. Then they made you sometime diagram out what the molecule looks like [dot diagram]. They never gave me a problem like your example that will be another chem problem to practice with. They used exactly half of test to ask general chem equations that some how they thought relates to env chem. The other half of test was a soil sample experiments and relate that work to how to make the soil better for growing crops. This event in the rules don’t have a limited on the questions they can ask. Yes they say that they should relate to the soil chemistry in the event but they really don’t have much relevance for what the rules intended.

Yeah, it's not uncommon for events to be heavy on the "Chem" and light on the "Environmental". Last year's B Division national event was a good balance, though. I think this problem- or just property, depending on how you see it- is mainly at the state level, although NY States this year was pretty good.

I agree... Our state test was about even, but it required knowledge of things like molarity and concentrations of ions in acids and bases.

Our regional and Invitational test, which were proctored by the national directer (I think her name was Lin W., but not sure), were not as heavy on the chem; instead, they were quite heavy on lab calculations such as porosity, permeability, bulk density, turbidity, mass spec, etc., and also heavy on contaminants and cleansing methods. She had nothing on the test about ions, equations, solution concentrations or anything else you would find on a chem test. Both tests were also not very heavy on the agriculture/crop aspects, instead focusing on physical properties of soils and a small amount of questions on major vs. minor nutrients.

[AustinRHL]

The test at Nationals was a joke, which really wasn't fair at all to teams that prepared hard for the event. We placed fifth with next to no preparation at all, aside from a notes sheet that I made that listed which elements were primary, secondary, and micronutrients, and what diameter the particles were in each type of soil. Most of the test was common sense or at least common knowledge (for example, naming elements when given their chemical symbol), and there were probably two things that actually differentiated the teams. One was reading the results of the nitrate and phosphate tests, which was next to impossible because the solution was much darker than the given colors, making comparisons guesswork. The other, which I think tripped up quite a few people, was balancing some equations that occur in soil, which wasn't especially easy because there were as many as four products to juggle in addition to charge. The tiebreaker questions were too easy, but they still should have been scored as regular questions, because they came the closest to actually testing knowledge of environmental chemistry.

[Phenylethylamine]

The test at Nationals was a joke, which really wasn't fair at all to teams that prepared hard for the event. We placed fifth with next to no preparation at all, aside from a notes sheet that I made that listed which elements were primary, secondary, and micronutrients, and what diameter the particles were in each type of soil. Most of the test was common sense or at least common knowledge (for example, naming elements when given their chemical symbol), and there were probably two things that actually differentiated the teams. One was reading the results of the nitrate and phosphate tests, which was next to impossible because the solution was much darker than the given colors, making comparisons guesswork. The other, which I think tripped up quite a few people, was balancing some equations that occur in soil, which wasn't especially easy because there were as many as four products to juggle in addition to charge. The tiebreaker questions were too easy, but they still should have been scored as regular questions, because they came the closest to actually testing knowledge of environmental chemistry.

The nitrate and phosphate tests worked out okay for me, although of course I have no idea if I got the answers right or not. Originally I had the two solutions in the wrong colorimeters, but I figured that out pretty much immediately, so it was okay .

The equations were redox (difficult to balance by trial and error), but the hardest part was that you had to add two equations together to obtain the third reaction for each question, and the added equations just didn't work if you did them by straightforward addition (my chemistry teacher says you had to add the reduction half reactions together and the oxidation half reactions together, and then do redox balancing on that).

The mass spec and gas chromatography parts were way too easy, though- you didn't have to know anything about MS or GC! They gave a mass spectrograph and a gas chromatograph, and some charts of mass fragments and things like that, and asked you to figure out which pesticide was depicted in which diagram based on the charts they gave you. It was ridiculous.