Environmental Chem C

[packer-backer91]

can anyone tell me if typed notesheets are allowed, I know in past years they had to be hand written and that both partners could have a sheet. Has this changed?

I am S.O> excited for state!!!!! only 2 more weeks!

yes but there is ONE sheet per team, and it can by typed with picture or graphs, anything and everything that you can get on a single page front and back is allowed.

[crazyredhead42]

Hey Guys,

There was a question from my Envi. chem Regionals test that I can't find the answer to.

Your neighbor John Brown, brought you the results he measured with a soil test kit of his soil. He found a pH of 6.20, The Phosphorous was very low, the Potash was optimum, and the Nitrogen was high. What fertilizer would you recommend if he wants to grow lettuce?

I answered a fertilizer of 5-10-10, but this was marked incorrect.

Does anyone know the right answer?

[peoneill]

That question is subjective and very difficult to answer in a specific way - your answer seems acceptable. Normally people use 10-10-10 for lettuce - REGARDLESS of if there's already a high level of potassium or phosphorous. I think the coordinator was trying to make you think you can use ZERO potassium since the potassium level is "optimum." Although your coordinator would be wrong - people just use 10-10-10 anyways, even if the potassium levels are already optimum. Lettuce does need plenty of phosphorous and potassium, so the low level of phosphorous may mean you want to apply a richer phosphorous source than that.

You certainly don't want to change the pH, that's totally lettuce's happy place.

[crazyredhead42]

Thanks peoneill!

Does anyone have a chart of acceptable pH ranges and Fertilizer levels for various vegetables?

I've made my own list, but since the questions are so subjective, I can put the right answer and it can be totally wrong!!!

I have the pH ranges for Tomatoes, Corn, Lettuce, Potatoes and Peanuts. Has anyone else encountered any other vegetables on their tests?

[kjhsscioly]

Does anyone know who is coordinating Environmental Chemistry at Nationals this year? Is it the same person from last year?

I don't know who did it last year, but I do know that it is our invites, regionals, state director who does Echem for nats

[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.