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AQA Science Questions thread

Hi guys, I thought this would be a good idea to help people that are working on AQA for Science and need some questions (specifically for the Triple units since there seems to be a shortage of exam papers :tongue:). Feel free to post any questions you may have, but I'll start for now :smile:

Why do isotonic sports drinks help when undergoing heave exercise?

Props to thechemistress for the idea :biggrin: (hope I spelt it right :tongue:)

thechemistress
X
Yep, you spelt it right :biggrin:
As for your question, I actually don't know which is concerning xD My textbook doesn't seem to cover isotonic drinks D: Do you mind explaining why? :h:
Original post by thechemistress
Yep, you spelt it right :biggrin: As for your question, I actually don't know which is concerning xD My textbook doesn't seem to cover isotonic drinks D: Do you mind explaining why? :h:
This is exactly what I mean, I'm looking for stuff that doesn't just pop up in the textbook :tongue: I'll spoiler it in case you want to try and have a go, but...

The isotonic drinks contain a similar concentration of ions and sugars to the usual bloodstream, therefore as they are used up during exercise the sugars diffuse into the bloodstream gradually causing a long term release of energy which is perfect for heave excercise.
Original post by silentshadows
This is exactly what I mean, I'm looking for stuff that doesn't just pop up in the textbook :tongue: I'll spoiler it in case you want to try and have a go, but...

The isotonic drinks contain a similar concentration of ions and sugars to the usual bloodstream, therefore as they are used up during exercise the sugars diffuse into the bloodstream gradually causing a long term release of energy which is perfect for heave excercise.


Ah, nice :biggrin: I'm doing the same, but just not for Biology xD As you can see from my name, Chemistry is my one true love :tongue:

Ah, okay. So I knew that isotonic drinks had the sante concentration of solute, but not the other bits xD
So a long tern release of energy due to sugars from the drink diffusing into the bloodstream as they are used up in respiration?
Thanks btw :biggrin:

Okay, Chemistry question coming up.
(a) There are five different tubes containing five different solutions. However, the labels on each of the tubes have come off. The five labels say the following: lithium chloride, aluminium sulphate, sodium carbonate, iron (III) iodide and magnesium bromide. Describe the different tests you would need to identify these substances

(b) Describe how you would find the relative molecular masses of the individual compounds of a mixture containing 3 different compounds. (Hint: chemical analysis).

Any difficult chemistry questions would be greatly appreciated :biggrin:
Great Idea! I need to find more questions for C3,P3 and B3 since there are only two past papers for each..
Original post by thechemistress
Ah, nice :biggrin: I'm doing the same, but just not for Biology xD As you can see from my name, Chemistry is my one true love :tongue:Ah, okay. So I knew that isotonic drinks had the sante concentration of solute, but not the other bits xDSo a long tern release of energy due to sugars from the drink diffusing into the bloodstream as they are used up in respiration?Thanks btw :biggrin:Okay, Chemistry question coming up.(a) There are five different tubes containing five different solutions. However, the labels on each of the tubes have come off. The five labels say the following: lithium chloride, aluminium sulphate, sodium carbonate, iron (III) iodide and magnesium bromide. Describe the different tests you would need to identify these substances(b) Describe how you would find the relative molecular masses of the individual compounds of a mixture containing 3 different compounds. (Hint: chemical analysis).Any difficult chemistry questions would be greatly appreciated :biggrin:
Ah, how I hate analysis :colonhash: So much pointless memorization :colonhash:

Halide test - Add HNO3 and AgNO3, white for chloride, cream for bromide, yellow for iodide. Carbonate - Add dilute acid, bubble gas through limewater, turns cloudy Sulfate - Add HCl and Barium Chloride, white precipitate. Lithium - Flame test, crimson flame. Sodium -flame test, orange flame. Aluminum - Hydroxide test, soluble white precipitate in excess NaOH. Magnesium - Hydroxide, insoluble white precipitate. Iron (III) - Insoluble brown precipitate.

GC-MS - Bombard with electrons to ionize, vaporize and pass through tube and then just read off molecular ion peak. That OK?
Original post by silentshadows
Ah, how I hate analysis :colonhash: So much pointless memorization :colonhash:

Halide test - Add HNO3 and AgNO3, white for chloride, cream for bromide, yellow for iodide. Carbonate - Add dilute acid, bubble gas through limewater, turns cloudy Sulfate - Add HCl and Barium Chloride, white precipitate. Lithium - Flame test, crimson flame. Sodium -flame test, orange flame. Aluminum - Hydroxide test, soluble white precipitate in excess NaOH. Magnesium - Hydroxide, insoluble white precipitate. Iron (III) - Insoluble brown precipitate.

GC-MS - Bombard with electrons to ionize, vaporize and pass through tube and then just read off molecular ion peak. That OK?


Oui, c'est vrai. Though for the last one, you haven't outlined gas chromotgraphy- you've just described mass spectrometry. But all good apart from that :h:
Original post by thechemistress
Oui, c'est vrai. Though for the last one, you haven't outlined gas chromotgraphy- you've just described mass spectrometry. But all good apart from that :h:
Soz, I don't do French :s-smilie: For the sake of completion... The ions have different relative masses and charges so they are accelerated at different speeds ( F=dρdtF= \dfrac{d \rho}{dt} ) and deflected by different amounts due to the magnetic field in the gas chromatographer, which can be detected by MS which gives an accurate reading of the masses of the elements.
Original post by silentshadows
Soz, I don't do French :s-smilie: For the sake of completion... The ions have different relative masses and charges so they are accelerated at different speeds ( F=dρdtF= \dfrac{d \rho}{dt} ) and deflected by different amounts due to the magnetic field in the gas chromatographer, which can be detected by MS which gives an accurate reading of the masses of the elements.


Impressive :biggrin:
Necro'd cos I can :colone:

What are the conditions required for the Haber process and why?

Posted from TSR Mobile
Reply 10
200 atmospheres - higher pressure favours forward reaction because fewer molecules of gas. Compromise- higher pressure would require more energy/cost more.

450*C - lower temperature = more ammonia because forward reaction is exothermic. Compromise - lower temperature = lower rate of reaction = less ammonia in given time.

Iron catalyst...I think? Provides a 'different pathway' for the reaction and lowers the rate of reaction = more produced in a given time.

^that's off the top of my head without revising it for a while so it's probably wrong.

Biology question: Compare/contrast conditions required for production of biofuels/biogas/fusarium.
Original post by odjack

Biology question: Compare/contrast conditions required for production of biofuels/biogas/fusarium.


Biofuels: I'm assuming by biofuel you mean ethanol based biofuels. Produced by the anaerobic fermentation of glucose (sugar cane), producing ethanol and CO2.
Biogas: Again, anaerobic fermentation of waste materials containing carbohydrates (plant material, animal waste). Methane and CO2 produced.
By fusarium, do you mean mycoprotein? Mycoprotein is produced in aerobic conditions by a fungus known as Fusarium which grows and feeds on cheap sugar(glucose) syrup.

So. Comparing and contrasting:
Well, the production of ethanol and biogas are both anaerobic processes whereas mycoprotein production is aerobic.
All three of them produce CO2

Yeah, that's all I've got.

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