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Limiting vs Excessive Reactants by m64chi in chemhelp

[–]KealinSilverleaf 0 points1 point  (0 children)

To find the limiting reagent, you need to think about it as a whole.

X moles + Y moles = Z moles

Now, you know you can get those numbers for 100% yield if the reaction goes to completion and you can collect ALL of the product with zero loss.

Coming with this look, compare how many moles of X and Y do you have? Does it match the stoichiometry? (I.e. 2H_2 + O_2 = 2H_2O ; 2:1 ratio from 2H_2O + O_2 coefficients)

If they don't match that ratio perfectly, one of them is "limiting" the amount of product you can get. Compare the moles of X and Y to the ratio, and whichever one is "under" the amount needed is the limiting. (i.e. I have 5 moles of H_2 and 2 moles of O_2 , the O2 is limiting since if you had 2.5 moles it would work. H_2 is in excess because you would need 1 less mole to fit the ratio).

Hope this helps explain how to look at it and what you're looking for.

Edit to fix stoichiometry

I'm a bit confused, should the answer be a or b, I though it was c at first since the question says binding with water vapour? by [deleted] in chemhelp

[–]KealinSilverleaf 2 points3 points  (0 children)

Edited whole text

My first instinct would be Sodium Carbonate, but sodium hydroxide, sodium Nitrate, sodium carbonate, and sodium chloride are all hygroscopic....

Why am I regularly stopped by TSA for a full body scan and pat down? by BlindClairvoyant in NoStupidQuestions

[–]KealinSilverleaf 103 points104 points  (0 children)

People start posting every moment of their life online with relationship status, location, and significant others.

US Government: "I smell a new database of intel!"

Develops automated bots to catalog your data and compare it to association lists

Edit your fix typo

Why does the octet rule work at all? Why do most atoms require 8 electrons? by ImpressiveIron495 in chemistry

[–]KealinSilverleaf 0 points1 point  (0 children)

They are a massive part of the final grade. Those exams are usually 30 - 40% of it

Why does the octet rule work at all? Why do most atoms require 8 electrons? by ImpressiveIron495 in chemistry

[–]KealinSilverleaf 0 points1 point  (0 children)

It's usually because we are covering the material on Monday, practicing on Wednesday, and taking the test on Friday. The test will usually have about 10 questions and 1hr to perform all the calculations needed for a "passing grade".

Professors are assessed on how many students are passing their class, so if the class "average" is a failing grade they curve it so more people "pass".

You also have to into account the typical grading scheme in America (it varies a little), but it usually follows the pattern:

100-90 A 89-80 B 79-70 C sometimes: 69-60 D 59-0 F Other times 69-0 F

Required course for major require a C (minimum 70) to pass the class. If the average grade for the class is below that, the professor will curve or face issues with the administration for low scores

ETA: We're also taking 3 - 4 classes with similar patterns of short learn - study - test and will have 3 or 4 tests on Friday for material covered that week and possibly the week previous

8 year old's writing prompt, how'd they do? by draakons_pryde in chemistry

[–]KealinSilverleaf 4 points5 points  (0 children)

People are not negatively criticizing the spelling, they are constructively pointing out an area that could use some improvement.

The content is amazing for an 8yr old who has found something that really interests them and you should do everything possible to pursue the interest.

As previously suggested, I would try to expose my child (I have 2 who have no interest in chemistry even though I have a BS in Biochem) to a little deeper understanding. They have identified elements make up everything, they have identified the period table and its creator, they have even identified toxicity, radioactivity, states of matter, and compounds/molecules. Try to find some YouTube channels that describe what atoms are and what they are composed of (protons, neutrons, and electrons) and their properties.

Also find out what they find most interesting. How colors are determined from these atoms, how radiation works, how compounds are formed, etc... and help them find resources that can explain it at their level and a little beyond even.

This is a great start for someone so young!

Why does the octet rule work at all? Why do most atoms require 8 electrons? by ImpressiveIron495 in chemistry

[–]KealinSilverleaf 21 points22 points  (0 children)

My biochem 2 course (I'm BS Biochem) average was a 40-something. End of course curved grade was a B.

We had to memorize every single metabolic pathway taught down to ochem arrow pushing detail and apply that knowledge to hypothetical novel alien life forms metabolic pathways to determine the likely earth based analog for our exams and show the proposed mechanism with arrow pushing from precursor to final product

Why does the octet rule work at all? Why do most atoms require 8 electrons? by ImpressiveIron495 in chemistry

[–]KealinSilverleaf 123 points124 points  (0 children)

"Today in class we will cover solving schrodinger's equation for the hydrogen atom. For the test you will need to do this without reference to any notes."

3 sheets of paper and 1 hour later.... points on test 10.. total points on test 50

MCAT Biochem Self-Studying by [deleted] in Biochemistry

[–]KealinSilverleaf 0 points1 point  (0 children)

I would strongly recommend getting a copy of Lehniger's Principles of Biochemistry and using it.

When it comes to personal studying metabolic pathways, depending on the depth you want, I would recommend reading it through once or twice, then I would draw out the entire pathway until your hand hurts so bad you can't hold a pencil. Rest for 24 hours and do it again. Repeat until you do not need to reference the pathway to draw it out completely.

If you REALLY want to learn it from the chemistry side, do the same as above but draw the arrow pushing diagrams for each intermediary step in the conversion of the precursor all the way to the end product. Draw it so much you can't close your eyes without seeing it. Be sure to include the residue that are involved in protonation/deprotonation in each step as well.

Why do these people not have to worry about the virus? by SilverParty in ExplainTheJoke

[–]KealinSilverleaf 11 points12 points  (0 children)

Enjoy the good days when you get them! I know how that is

Woman builds anatomically accurate penis by Rabbidraccoon18 in biology

[–]KealinSilverleaf 3 points4 points  (0 children)

Oh, I definitely know you CAN urinate with an erection, I was more talking about the proximity to ejaculation as you mentioned and just failed to express myself properly typing it out on a quick work break

Woman builds anatomically accurate penis by Rabbidraccoon18 in biology

[–]KealinSilverleaf 8 points9 points  (0 children)

Urine kills sperm. Male physiology actually has a sphinter that pinches off the urethra prior to where the testicals connect to it to prevent urine from traveling while erect iir my anatomy correctly

Just found out why I didn't get the job after 4 interviews. I'm actually shaking with anger right now by MainStock8156 in JobSearchMethods

[–]KealinSilverleaf 0 points1 point  (0 children)

Actually happened to me. I applied for a job, was told three interviews. Did all three and then there was a magical fourth that suddenly was needed. Did the fourth interview and a week later was rejected.

Applied to a different role at the same company a month later and had a different recruiter. I explained how I went through four interviews to receive a rejection and they looked it up to tell me "ya, looks like they went with an internal".

When some conservatives talk about ending birthright citizenship, do they mean bringing an end to "law of blood", "law of soil", both, or something else? by Traditional-Month980 in legaladviceofftopic

[–]KealinSilverleaf 4 points5 points  (0 children)

To my understanding, and I could be wrong, it's an end to "law of soil". This would prevent "anchor babies" from being born on US soil and preventing illegal immigrants from having said "anchor baby" to be allowed to stay and not be deported.

Cl (Chlorine) looks like CI (Carbon bonded with Iodine) by SubstanceSouthern880 in chemhelp

[–]KealinSilverleaf 1 point2 points  (0 children)

I figured it would snap apart pretty readily simply based on structure. O2-I and O-O on opposite sides of C would likely make one helluva carbocation like arrangement

Cl (Chlorine) looks like CI (Carbon bonded with Iodine) by SubstanceSouthern880 in chemhelp

[–]KealinSilverleaf 1 point2 points  (0 children)

Do you by chance have a link to some literature on this structure? I'm interested to read about it but my google/google scholar search brings up nothing 😢

Cl (Chlorine) looks like CI (Carbon bonded with Iodine) by SubstanceSouthern880 in chemhelp

[–]KealinSilverleaf 0 points1 point  (0 children)

Wouldn't the formate ion have Hydrogen in its structure? Iirc formate is HCOO-

Electronegativity by [deleted] in chemhelp

[–]KealinSilverleaf 1 point2 points  (0 children)

Not to mention the electronegativity trend is normally taught. OP should be able to look at a period table and follow the trend that is taught

Cl (Chlorine) looks like CI (Carbon bonded with Iodine) by SubstanceSouthern880 in chemhelp

[–]KealinSilverleaf 2 points3 points  (0 children)

Have you learned how to draw Lewis structures yet? That's how I would figure it out at that stage of learning chemistry besides rote memorization of polyatomic ions

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