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maths differentiation help!!

hi guys got some practise maths questions any help will be appreciated .
q1) PH= -log base 10[H+]
WHAT IS dpH/d(H+)?
q2) PH= 2.5 - 1.5 e^-t/4.5
many thanks
Original post by ono101
hi guys got some practise maths questions any help will be appreciated .
q1) PH= -log base 10[H+]
WHAT IS dpH/d(H+)?
q2) PH= 2.5 - 1.5 e^-t/4.5
many thanks


What have you been able to do so far?
Original post by ghostwalker
What have you been able to do so far?

for q2 i differentiated by bringing the t to the front and then when i simplfied i got my answer as this is it right; dPh/dt= -1/3 e^-t/4.5 would that be correct

and for q1 i have no idea
Original post by ono101
for q2 i differentiated by bringing the t to the front and then when i simplfied i got my answer as this is it right; dPh/dt= -1/3 e^-t/4.5 would that be correct

and for q1 i have no idea


Q2. Very close. You just have a sign error. -1.5e^-t/4.5 would differentiate to -1.5(-1/4.5) e^-t/4.5, leaving us a plus sign at the front.

Q1. You want to convert to the natural log base (e), then differentiate. Do you know how to do that?
Original post by ghostwalker
Q2. Very close. You just have a sign error. -1.5e^-t/4.5 would differentiate to -1.5(-1/4.5) e^-t/4.5, leaving us a plus sign at the front.

Q1. You want to convert to the natural log base (e), then differentiate. Do you know how to do that?

so for q2 it would be +1/3 e^-t/4.5?
and hmm im in year 13 and i love chemistry and want to take it as a degree so my teacher likes too give me maths problems cause theres a lot of maths in chemistry and i dont do a level maths so i dont think i do i know its -1 on the numerator but im unsure that one was a multiple choice though
Original post by ono101
so for q2 it would be +1/3 e^-t/4.5?
and hmm im in year 13 and i love chemistry and want to take it as a degree so my teacher likes too give me maths problems cause theres a lot of maths in chemistry and i dont do a level maths so i dont think i do i know its -1 on the numerator but im unsure that one was a multiple choice though


Q2 Yes. +1/3 e^-t/4.5

Not clear what you're refering to with that bit - highlighted in red.
and then i also have one more thats very weird;
E=0.232 + 2.4*10^-2 T - 3.6*10^-4 T^2
what is DE/DT?
never learnt it but a bit of self teaching lol i did get two answers have no clue which is correct though ;
my answers i know 0.232 dissapears its a constant right?
2.4*10^-2 T -7.2*10^-4 T^2 and 2.4*10^-2 - 7.2*10^-4 T
Not sure though narrowed it down was. a multi choice again out of 5 chocies
Original post by ghostwalker
Q2 Yes. +1/3 e^-t/4.5

Not clear what you're refering to with that bit - highlighted in red.

oh referring to answer -1/0.434[H+] but im unsure never really done ones this hard she goes it comes later but i guess shes trying to push me
Original post by ono101
and then i also have one more thats very weird;
E=0.232 + 2.4*10^-2 T - 3.6*10^-4 T^2
what is DE/DT?
never learnt it but a bit of self teaching lol i did get two answers have no clue which is correct though ;
my answers i know 0.232 dissapears its a constant right?
2.4*10^-2 T -7.2*10^-4 T^2 and 2.4*10^-2 - 7.2*10^-4 T
Not sure though narrowed it down was. a multi choice again out of 5 chocies


2.4*10^-2 - 7.2*10^-4 T is correct.
Thanks ghost Walker you’ve been a great help I’m off school till January so i really appreciate your help you’re really good at maths :smile: .
Original post by ono101
hi guys got some practise maths questions any help will be appreciated .
q1) PH= -log base 10[H+]
WHAT IS dpH/d(H+)?


Think I'm going to have to do this one for you as you're not studying maths.

pH= -log base 10[H+]

= -log base e [H+] / log base e 10

[The derivative of log base e of x is simply 1/x]

This gives us d(pH)/d(H+) = - (1/[H+]) * (1/2.3026...)

= -0.4343/[H+] quoting the constants to 4dec.pl.

which is slightly different to what you have.

But, you really need to study some maths. My going through this isn't going to help much, and we don't usually do a full solution - forum rules. I make an exception here as you're not studying maths.
(edited 3 years ago)
Oh okay thanks tht was the final question . The first 10 were easy just the last 3. Thanks for your help bud I really appreciate it.
One more thing how would I get better at maths like were so I start cause I haven’t done maths but my teacher says my degree requires a lot of integration. And differentiation?
Many thanks
Original post by ono101
One more thing how would I get better at maths like were so I start cause I haven’t done maths but my teacher says my degree requires a lot of integration. And differentiation?
Many thanks


Not the best person to ask on this; not being a teacher.

My thoughts: You're going to need to work through material that builds up methodically, so a book aimed at A-level would be useful as a basis from which you can pick and choose which areas to look at in the order in which material is presented. Or possibly just a revision guide that would give you the main results and practise, leaving out the theory behind it all. As you're not doing the A-level, I wouldn't attempt to take it all in.

That said, your chemistry teacher might be the best bet for deciding which areas to focus on and which you don't need to look at, and possible also for which book to go for - if any. She may also have other ideas of how to proceed, but I would certainly discuss it with her.
Okay thanks I appreciate it, have a good week (:
Original post by ono101

One more thing how would I get better at maths like were so I start cause I haven’t done maths but my teacher says my degree requires a lot of integration. And differentiation?
Many thanks


It's probably worth creating a thread in the A-levels forum with a title along the lines of "Doing Chemistry A-level, but not maths. Advice please", and explain your situation.

Forum url is https://www.thestudentroom.co.uk/forumdisplay.php?f=80
See chemistry as an A level has very manageable easy maths like I’ve consistently got A’s and B’s in chemistry this year and last . But apparently it’s a step up at uni should I just post it in a uni forum or ? The organic chemistry tutor on YouTube is really good I learnt basic integration and differentiation from him. What did you do at university?
Original post by ono101
See chemistry as an A level has very manageable easy maths like I’ve consistently got A’s and B’s in chemistry this year and last . But apparently it’s a step up at uni should I just post it in a uni forum or ? The organic chemistry tutor on YouTube is really good I learnt basic integration and differentiation from him. What did you do at university?


I did maths at uni. If you're looking at the maths requirement for your chemistry A-level, then I would put it in the A-level forums. I did chemistry as well at A-level (long time ago) and the questions you posed in this thread were, to my mind, definitely A-level.

I can't speak for uni. level chemistry, but would expect it to be a significant jump from A-level in terms of maths requirements.

I believe there are a lot of good videos covering maths on the 'net, though I can't recommend any - others probably can.

I just did a quick google "maths for chemistry a-level" (without the quotes) and several books come up; worth a look.
You’ve been a great help I really do appreciate it . And fair play I rate anyone whose done a sciencey degree good for you man. Thank you again

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