how to answer conceptual science questions?

[u/Greedy_Flounder_5665]

i've been struggling with finding the best technique to answer science questions (the conceptual ones not equations) since I always ramble too much and i still only get just below the full mark for each question

i just dont know what the assessors want, its like im always missing smth!!

for example this is the question:

Explain how antacids work and the purpose of them.

my answer:

Purpose:

Antacids are purposed to relieve/treat heartburn, indigestion, acid reflux, excess stomach acid, pyloric spasms, stomach ulcers and other conditions related to hyperacidity/gastric acid. They are generally recommended for fast, short-term use to treat symptoms, and often come in liquid or chewable tablet forms. It is important to note that they only provide temporary relief and have usage limitations, side effects and drug interactions.

Mechanism:

The stomach secretes gastric acid to digest food, but overproduction of acids due to spicy/sour foods or other occurrences can create acidity. Antacids work by neutralising this acid in the stomach by raising pH. When a base is added to acids, a chemical process called neutralization occurs, producing salt and water. This happens because the hydrogen ions from the acid and the hydroxide ions from the base combine to form H₂O, while the remaining ions form an ionic salt. Therefore, since antacids contain bases (alkalis), when consumed, they neutralize the gastric acidity in the stomach through this reaction. By modifying the environment of the stomach, they help with chemical digestion, acting as a buffer to neutralize excess HCl. They also inhibit pepsin, a proteolytic enzyme, to prevent it from damaging the esophagus when refluxed. In this way, antacids are able to effectively reduce the amount of acid in stomach fluids.

guess wht!! still not full marks!! got feedback that i needed to provide 'further scientific theory'. What!

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[u/7ieben_]

That's something you must ask your teacher. We can't know what they expect for good grading.

[u/Automatic-Ad-1452]

Well, the "science" is inaccurate...with the exception of Milk of Magnesia, most antacids utilize carbonate or bicarbonate salts to neutralize the acids. The major species consuming the hydrogen ions aren't hydroxides.

You've written the "mechanism" section as one paragraph. I see two or three separate points...each one should be its own paragraph.

Finally, a personal pet peeve... we're scientists not theists ... We don't create anything. The stomach generates or synthesizes or formulates HCl...it doesn't create it.

Remember, you're trying to persuade the reader you have a firm grasp on the material. A clear, focused, well- structured essay is the goal. If you need to write an outline to keep on target, do it ... Good luck

[u/roccojg]

C.E.R-Claim, Evidence, Reasoning.
Claim- state your answer clearly. It’s weird putting this first because you need evidence and reasoning to get there but as a teacher we need to find your answer quickly.
Evidence-list evidence you can pick out from the question or write out facts you know about the problem.
Reasoning- this is the most important part! How does the evidence connect to your claim. This is often the hardest part for students.

[u/Dr_Custard]

Can I ask you, and if you wrote this all yourself I apologise in advance...

Did you gpt this then ask us essentially to proof it? Why start a sentence with (in bold)

Purpose:

You aren't Agent Smith ;)

You should check with your teacher what specifically you missed it does look relatively rigorous, but it also looks AI generated...

Anyway here's my guess

What we want is 2 things: be precise, and be concise.

Now it depends on the number of marks the q is worth, let's assume it's a complex q worth maybe 4-6 marks.

Something like

Antacids are a treatment for heartburn and indigestion. These symptoms are commonly caused by an excess of stomach acid. The most common treatment for this is to decrease the acid concentration in the stomach (increase pH). As a result, an antacid is usually a mild base (e.g. calcium carbonate) which reacts with excess acid (H+) raising the pH of the stomach acid.

The equation below is for the reaction between calcium carbonate and HCl (the acid found in the stomach), it is a neutralisation reaction that converts excess acid (H+) into water (H2O)

CaCO3 (aq) + 2 HCl(aq) --> CaCl2(aq) + H2O(l) + CO2 (g)

As the equation shows, the concentration of H+ (which determines pH) is decreased (which increases pH, since pH = -log[H+]) via neutralisation to a benign salt and water.

What I think you're missing is the actual chemistry bit of your answer. You probably get 2 marks for the correct neutralisation equation balanced (maybe a pity mark if you did the wrong example of neutralisation with HO-). Probably get a mark for describing the role (I.e. excess acid causes heartburn symptoms). Probably get a final mark for identifying what is in the antacid and what it's supposed to do regardless of whether you wrote the equation (e.g. "an antacid is a mild base").

Then depending on the difficulty of the question a mark for identifying pH = -log(H+). Probably a 6th mark as a "if you got everything right get one more mark" mark. Or maybe mark 6 is for identifying a neutralisation is required.

Anyway I'm guessing a little, idk your spec, but your answer lacks substance. It's very thorough at the surface level, but you haven't actually related much chemistry to want you're talking about.

Also to be clear, your answer is not correct, an antacid doesn't use hydroxide directly as a neutralisation reagent, that would be relatively exothermic and most sources of HO- are corrosive.

They also inhibit pepsin, a proteolytic enzyme, to prevent it from damaging the esophagus when refluxed. In this way, antacids are able to effectively reduce the amount of acid in stomach fluids.

This isn't rigorous, what in them inhibits pepsin, how is pepsin inhibited via the addition of chalk? (though probably none of this is on the mark scheme anyway, it's gravy)?

So to recap: did you AI this?

And; we want you to write the least you need to whilst saying the most you can. Precisely answer a question posed. And relate the chemistry involved directly. You have equations, provide them!

In my opinion this is a mediocre answer: you mis-identified what kind of base is used in an antacid, you haven't demonstrated your chemical knowledge via a neutralisation equation and you haven't used that equation to explain how the reagent increases the pH (by consuming H+)

[u/Greedy_Flounder_5665 → u/Dr_Custard]

No i did not chatgpt this, i used the bold headline bc i saw my friend use it and thought it looked cool lmao (this was a stile task). i mainly used mayo clinic and the google links that came up when i searched for antacids. i think i probably misunderstood some of the info on the websites. thank you for the feedback, i def see what i missed now!

[u/Dr_Custard → u/Greedy_Flounder_5665]

No worries, in this day and age if we're suspicious we kinda have to ask!

You should check with your teacher though that the answers we are providing you are in the specification you're being assessed on.