Spectrophotometry and Beer's Law

We've learned about kinetics already, but how do we gather kinetic data? One clever method is by analyzing how the color of a solution changes over time, which is an indication of the concentration of certain compounds that interact with light in a specific way. This technique is called spectrophotometry, and this type of analysis will involve calculations using Beer's Law. Let's take a closer look!
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I'm Scott Beer and I approve this message.

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Hi Scoot Beer. My name is not Scott Beer.

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[@TasTheWatcher]

Beer's law? Aye, I'll drink to that.

[@Thaumius]

*Beer Lambert Law*

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Me too

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[@rauter828]

@@masterally6025 I understood..I never tried..just to know what will be d reply..

[@dumitru-claudiusergentu6720]

Hi Dave, since A is log (I/I0) and A is e*b*c, then I = I0 * 10^(-ebc), not I0*exp(-ebc) because it is not a natural logarithm but a base 10 logarithm.

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I can't explain how to thank you .Tomorrow is my test and now I'm feeling relax.

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I love being able to understand something!

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You're not professor Dave...

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Um, yes, I am Professor Dave. The channel is called Professor Dave Explains. See?

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It's because of the short hair isn't it😂😂

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​@@ProfessorDaveExplainsproffessor u gonna let the imposter slide?

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​@@ProfessorDaveExplainsUmm, that made us more sceptical 🤔

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Thanks a lot Professor Dave, you are literally a life saver

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he is he has canonically saved over 200 people from trains, mugging and chemistry mishaps. This is his penance as professor Dave caused the 2011 Fukushima Nuclear Disaster

[@alexting827]

@@slow_bike_show :O??

[@tommysteinbrecher]

Wow I was just lectured about this in chem and now studying for the midterm in 2 days what’re the odds hell yes professor dave

[@yolo_earth]

Thanks for your video, Professor Dave! one thing to mention, it might better to tell log used here is actually base with e, not 10. In context it explained greatly, but itself I got bit confused for secs.

[@jerryhymytang8859]

Hi professor Dave, I realized that you convert the log with a base of 10 to a exponential with a base of e, shouldn't it be in the base of 10? or else a natural log should be used instead of log in the base of 10

[@muthegameonline]

I also thought the same

[@GameHero531]

It's unfortunate and rather annoying but some textbooks and professors use log to mean "log base e", while others use it to mean "log base 10". It makes sense to just call log base e "log" if you know where the logarithm operation originally came from, but it's confusing nonetheless

[@CMThota]

​@@GameHero531 so basically he meant log base e (ln) not log base 10? (the terminology is a bit new so just clarifying :))

[@GameHero531]

@@CMThota correct

[@autonews1621]

thanks bro, so annoying

[@sunflora27]

thanks professor dave! This helped reiterate what my online course just blew through rather quickly

[@rebornmmmmuch]

Very well explanation. Now I get the idea what this is all about🙏🏻

[@funnyseasonalnews8193]

Thank you professor Dave I have got relevant notes

[@williamadams137]

Is “log” log base ten? Because i usually see people use “Log” or “ln” for natural log.

[@ProfessorDaveExplains]

yep if the base is not specified it's implied to be 10

[@yunus-ff2mw]

@@ProfessorDaveExplains Also, in our experiments, we took the logarithmic as 10 instead of e.

[@nickelpence]

Just shared the video with a friend who didn't understand wery well what they did just today at chemistry class😉

[@vicentesayson2990]

Do you think sir, it's a good idea to create a spectrophotometer using specific wavelength only? For water analysis?

[@ProfessorDaveExplains]

seems like an arbitrarily limitation to me

[@vicentesayson2990]

@@ProfessorDaveExplains can you explain further? By the way sir, I conducted some experiment using pasco spectrometer, i see that at 650nm wavelength the water absorbance of a distilled water is 0 , that's why i'm thinking to use 650nm as a standard source of light to determine the impurity of water

[@Ajay-Maurya.]

@@vicentesayson2990 anything would do right? light absorved same?

[@sammyapsel1443]

Can someone point out the following: If Transmittance is defined as I/I0, then why isn't Absorbance defined as A=1-T , but rather as A=-log(T)?

[@sammyapsel1443]

What does then 1-T signify? The percentage of light that doesn't get transmitted which is not the absorbance?

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[@brianbaas8650]

Nice first like and Comment! Loving your channel Bro, I always learn something from you 👌🏻👍🏻😁😎

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One of the best channels in the field

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[@LittleWaffle]

Thank you for this well-explained video !

[@antoniocurcino9976]

Thank you so much for the explanation!

[@ellavaldivia6757]

Thank you professor David for this video.

[@joshmemarrynagdey1639]

Thanks a lot... you make the topic easy to understand.

[@namithacd5650]

Can you do one for thin layer chromatography? Would be greatly helpful!

[@jimpanse1638]

Why is the number of moles a concentration? Isnt the concentration moles/volume? How can i get the total number of moles in the cuvet?

[@evelynvarsovia3380]

Very clear explanation. thanks prof Dave

[@TommyZommy]

Dave, are you considering making computer science lectures?

[@ProfessorDaveExplains]

yes definitely one day!

[@scigrl2870]

Hello, thank you for your videos - I show them to my undergraduate chemistry classes on occasion. However, there is an error in this video - the opposite of log is 10^x not e^x

[@kamilewais-orozco9971]

e^x is a notation for 10 to a power

[@kamilewais-orozco9971]

John Cavanaugh it doesn’t, but it’s helped me sort it out in my head

[@krellemaster]

log(x) is ambiguous and can be used to represent both base e and base 10. It is exceedingly common to use it as base e in physics.

[@Ajay-Maurya.]

​@@kamilewais-orozco9971 e is a special constant appearing in nature

[@gria8329]

On the example why is the initial intensity 1, where did that 1 came from??

[@ronanclark2129]

Hearing all these numbers made me anxi😢us about my homework so maybe I'll watch the rest another time

[@woomp2004]

I thank you from the bottom of my heart

[@fabioverdi6291]

Help with a question ????? A compound absorb light in 227 nm. The standard curve calibration for the compound is Abs = 372x + 0,6432 which the concentration is g/100mL. The technique was analytical standard adding from fluoxetine hydrochloride (C17H18F3NO.HCl - molar mass = 345,79 g/mol). So determine the concentration in mol/L from the analysed solution. Show all calcs progression.

[@jagrutipaneliya4548]

Could you give me a name of software where I can plot my graph in better way?

[@rosapizana8597]

My professor used the example as an activity for the class but she asked which compound the measurement belongs to and I have no idea how to determine that.

[@tnjoegaming2458]

Sir can u pls give a lecture about calorimeter principles and its application..

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Proffessor Dave, I love you.

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thanks professor dave really helpful

[@pritykarmakar4937]

Thank you so much sir🙏

[@Mt.Trashmore]

Literally perfect timing!

[@sivasankar3349]

how 0.35 came for molar absorptivity?

[@mermerrrrrrrrr]

Thanks for your helpful videos

[@bennettegaper4344]

Thank you

[@ayeshariaz8380]

Is the value of incident light always taken as 1?

[@cliffordwilliams9597]

I'm confused how did we go from log I/i0, to e to the power of stuff?? Should it have been ln I/i0?????

[@12uullaass12]

I think he made a mistake he mistook log(I/i0) with ln(I/i0). it should have been I = i0* 10^-(epsilon*b*c)

[@aniawo5119]

Very useful. Thank you.

[@organicnky7448]

My favorite on internet 💎

[@TheEmperorjun]

Thanks a lot professor...

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Thank u professor Dave💗

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thank you for this!

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Thx 4 U'r effort ♥️

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i love you so much istg thank u 🥺 for ur content ❤️

[@AnyanwuPeterIkechukwu-nw4ri]

Please professor Dave, why do you use Iø as 1?

[@leenabulaban8450]

did you get an answer?

[@douniaelba4603]

Hi professor Could you do a video about asanning electron microscop plz

[@daviskimani1890]

Hey professor can you explain on how to calculate percentage transmittance. please😊

[@setsu2221]

Absorbance = 2 - log_10(%T) Example: 1 = 2-log_10(T) T = 10%

[@quintonwilson8565]

Great vid, wish I saw this earlier.

[@mansurie]

helped a lot thanks!

[@yarlankini2170]

Awesome 👍

[@guttipavan9306]

easy understand. tq sir

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u saved my life, thank you

[@استبرقابراهيم-ط1ر]

Thank you so much 💓 💗

[@scott_meyer]

Beer's law? Drink it.

[@leenalsader8476]

Thanks 🌸

[@axediepied6993]

THANK YOU!!!

[@adduct99]

How is the path length selected?

[@ProfessorDaveExplains]

it's the length of the cuvet

[@جهادالحربي-ق4ظ]

This relate with physics or biology???

[@eewls]

Thanks

[@salmaalmunayes4251]

What was it about bonding? It wasn’t explained

[@konstantinrebrov675]

Can you teach us how to make beer from a chemist's perspective?

[@ashishbhattacharya2807]

Thanks..

[@rassimsimou1594]

Good

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I'm August beer and i approve this video

[@nwerd]

Clint david sala and James Hendrick Aban Shourtout🎉

[@FarukUmarBello-eq1zu]

Please how did our I become 1?

[@leenabulaban8450]

did you get an answer?

[@KituPattnaik-m2s]

It's a reference to 100%... If we call 100% as 1 then other percentage are that fraction of 1 😊.

[@leenabulaban8450]

@@KituPattnaik-m2s thank you

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PROF. DAVE LANG MALAKAS (in filipino-only prof.dave is strong)

[@abuhureyraat-tijani6113]

2:50

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Anyone else have a broken Spec 20 for lab?

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Verification of beer lambert law through colorimetric

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nice cut

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Fuck you're good Prof Dave

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I like the look

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Good vedio ♥️

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can please someone do a remix of the intro. I am talking 24h version

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Anyone here to learn all of AP chem for the 2020 exam? ~We're all in this together~

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the hairstyle is weird to me

[@austinlincoln3414]

lol

[@alizedan3442]

Greaaaaat

[@doriankiss1]

When it says log, I guess that's the natural log, ln.

[@petranuth7112]

Beer Lambert's Law

[@niharikavase3387]

It is tough 🙁

[@curtpiazza1688]

👍

[@blaket5346]

Plotting in real time with a computer? That’s just code for “undergrads”.

[@yayapuncio497]

the more of a substance the light travels through

[@yayapuncio497]

the more of it that will be absorbed

[@yayapuncio497]

the higher the concentration the more of the substance will be absorbed

[@AR-gd6yo]

3:18 I got lost here

[@uguuuguunen9544]

kzbin.info/www/bejne/ranVcniCmr2fm80 at around 2:35 he visualizes that and it made sense

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👍👍👍

[@jmcadoesvids359]

This would have been useful 3 months ago, when i was actually seeing this shit in college