GCSE Chemistry Revision "Using Moles to Balance Equations"
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- Опубліковано 8 лют 2017
- GCSE workbooks www.amazon.co.uk/Dr-Shaun-Don...
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In this video, we learn how to use moles to balance chemical equations.
This video is based on the AQA spec. If you are following a different exam board then you should check your specification. The Amazon link above is an affiliate link. This provides a small commission which helps to support freesciencelessons. The cost remains the same to you. If you prefer not to use this, you can search Amazon for the Freesciencelessons workbooks.
I have to admit, I do feel quite smug when he says "higher-tier only" even though half of the country probably takes higher..
Well only VIPs know how it feels when he says triple students only
@@fireemperorzuko8756 fr, i feel like a genius
@@f_ldn_9398 sameeee
@@fireemperorzuko8756 oh god u dont understand how relieved i am when he says triple only, atlast i can take a break lol
so true
Thank you so much! Absolutely brilliant teacher and such a selfless person for providing such a brilliant service for free : )
he gets money off it from ads otherwise he would be charging
SuperSaiyanVader yeah we get it for free
@@yousefkhalil3052 yes but do we have to give anything to watch these? No, so that makes it free for all of us. Stop finding the negative in everything positive, he does need to provide for himself and family too and for what he has done for possibly millions, a few ads could never repay him for the amount he gave us.
@@fireemperorzuko8756 Read my name.
@@shush1402 Fire emperor is right. Not everyone devotes themselves to this caliber just to make revenue off some ads. He also sells revision workbooks for really good prices that are extremely useful. Shaun is devoting his time for us students, and our GCSE grades. Let’s be grateful, i don’t see many people making such effort, let alone for free. Not even some teachers, who are actually paid.
why does my teacher make this seem so hard when it was pretty simple
Same here
Cuz most teachers (mostly the ones I came across in middle and high school) dont prepare lessons and just teach on point that is why they trip on their explanation. Mr Donelly prepares his lessons carefully and doesnt make it very long so that we cant understand it well and dont need to take a very long time to revise the lesson watching his vids. Oh and he also gives lots of examples, easy and hard.
Same here. I think it’s because my teacher started us off with questions involving non-integer quantities of moles.
Fr i literally thought this was one of the hardest things on paper 1
why does the textbook make it so hard??
YOU'RE A LIFE SAVER THANK YOU. I have a teacher thats not that great at teaching and my exams are in 1 month and stupid me i just realized hw far behind i was especially coz im doing triple science so i started frm scratch and ur vids are helping a lot so THANK YOU and carry on doing ur job coz ur definitely one of the best at it
HOW DID YOU DO??
Heya I don't understand how he finds the number of moles? Could u help me please :)
Stardust Fallz Moles = mass/Ar or Mr
@@ginanicholson2490 Moles = Mass (g) / relative atomic mass (basically the top number)
How did you do?
OH MY GOD MOLES ACTUALLY MAKES SENSE.
my teacher spent so many lessons teaching us moles and i still didn’t understand till i watched your videos about them. you’ve managed to teach me moles in 30 mins and i acutally understand it compared to my teacher who spent a whole year teaching us it.
thank you so much sir i really appreciate it
YOU LEGEND!!!! IM FINALLY UNDERSTANDING CHEMISTRY!!
I understand everything! You're the best teacher ever. Thanks so much
no u dont
Oof
Oof
Thanks for the great lessons and generous sharing of all this content
hands in the pockets what a bad man
genuinely what a top geezer🙏 in 5 minutes youve thaught me more than my teacher has for the past 3 months
Fliiping love these videos- really clear and strsight to the point. Thank you so much for sharing I would pay for this if it wasn't free
thanks for sharing your lessons with us, theyre really helpful and informative
You’re defo the best teacher. Fairplay
I literally could not Chemistry twice throughout my life (many many years ago and many years ago) . Now I love it. Amazing teacher!
Thanks for the comment. I'm very happy to have been able to help.
Thank you very much
My teacher confused me and the whole class by her explanation but u uncleared all my doubts
Thank you again
This channel is excellent. Although our curricula are different, I direct my American students here for the no-fuss approach.
Thanks again, this really helped!
Thank you for blessing me with your knowledge!
i really love your teaching
thank you so much
my love for this man is unreal
You've helped so much, I hope you know you're doing something great and it's really helping a lot of us out here
Thanks for the comment, I really appreciate it and I'm glad to hear that I'm helping.
Damn, freesciencelessons with that ratio
@@CrappyEntertainment fr lmao
Than you for this video! Can I know where can I get the link to access the revision workbook
Love 4:54- my favourite part! Thank you so much, I was struggling with every aspect in chemistry and now get almost all of it!
😫😫mine too
Thanks for making this easy for me to understand.
you are a life saver
thank you so much !
thanks for the video, so helpful ✨
Hello sir your videos are so useful please can u tell me should I past papers without revising or with revision because I tried this way by putting the past paper questions on a flashcard and learning the mark scheme revising at the same time.
Shawn you SAVED MY LIFE
(PLEASE REPLY)Hi, can you please release A-Level Biology and Chemistry videos as because of you i have really enjoy Science now and want to pursue A-Level Sciences. Thanks!(PLEASE REPLY)
Hi. I will be making more A level videos in the future but that won't be for a long time I'm afraid as the videos for GCSE need remaking as the specification has changed. However, it is something that I will be doing.
can you do it for next year in august to start me off when I'm in sixth form thanks XD
Thank you! Amazing video
the best science teacher ever now i dont have to focus that much at school thanks sir!
To those who have a Chemistry this year... you are in the right place.
I passed in chemistry because of you thank you very much❤❤❤❤
I'm literally only using your videos to revise for my GCSEs
Thanks only helpful video on this I could find
to find the Mr you have to multiply the numbers right?
OMFG i finally understand this now !!! thank you
Yo 4 years ago what did u get on your GCSEs 😂😅
When dividing by the smallest number, and it's a decimal, do we just leave it as a decimal in the equation? Like if the smallest number is 2 and there's a 3 somewhere else in the equation, do we give it as 1.5?
Sir your videoes r helping me in gce
THIS MAKES SO MUCH MORE SENSE
if i just balanced these equations by seeing how many atoms there are but it was laid out like this, would I still get the mark for the right number in front because the atom way for me is much quicker
what does (II) mean written after an element?
would we always be given the symbol equation for example AI+FeO arrow AI2O3+Fe
and would they tell u which one is ironoxide lets say we did not know it?
Will you always be given that mass of each element or compound when required to balance it in the exam? Or are you given the choice whether to balance this equation using the mole method or the other? Thank you.
i think it depends on the question
how to find the relative formula mass of Al2 (SO4)3 at 3:50?
Al2(SO4)3 has 2 atoms of aluminium (27 each), 3 atoms of sulfur (32 each) and 12 atoms of oxygen (16 each) giving us a total of 342.
how do u get th mr I'm soooo confused
this guy is the BEST
do i need to learn this? surely in an exam i can just balance it the other way? or will there be a question specifically askkng me to balance it this way?
very nice. please give many videos.
Do we have to do it this way?
Thanks! I'm not afraid of chemistry anymore
Hi sir, how do we find out the relative formula mass of Hydrogen chloride as it isn't stated in the question? Many thanks
H = 1, Cl = 35.5.
HCl is (1x1) + (1x35.5) = 36.5
If the mole is a decimal number do we round it to the nearest whole number. I did 684/262 which got me 2.6..
Hi, on the last example, for Al2(SO4)3 I got 2.4 moles, but you put 2, have I messed up the equation or are you just supposed to round to the nearest whole number? Thanks!
No, I think you've made a mistake I'm afraid. The relative formula mass of Al2(SO4)3 is 342 which gives us 2 moles. You would very rarely ever round to that degree in any moles question.
my g absolute legend
thankyou sir u helped a lot
I have never really understood this after about 5 lessons but in 5 mins he has taught me it.
Where can find your Edexcel workbooks?
If you end up with the number of moles as a decimal like 3.5 do you still divide the ratio by the lowest mole or do you find the lowest common multiple of all the moles
thanks a lot, very helpful! but one thing keeps bugging me don't you ever move your right hand?
Thanks for the comment. When I'm talking, I'm actually reading from a script that I prepared. It's on an autocue which the viewer cannot see. My right hand has a clicker which moves the script along.
thank you so much, but i have a question. What happens when you divide by the smalles number and u get a decimal? For example i have 3NaCal and 2Mg2O in my equation. I divide by 2 id get 1.5. So do i put 1.5 infront?. thanks
Hi. Generally you don't put decimals in balanced equations (there is an exception, which is a combustion equation but your example is not one of those). In the case that you describe, you would need to double EVERY large number to convert the 1.5 to 3.
is this empirical formula???
would this come up for science btec exams tomorrow ?
how do you know what the relative formula mass is mr?
You work it out by adding the relative atomic masses.
Hi sir ,do you cover everything we need to know for the exam or brief summarys ?
I cover everything in the spec. The exam will expect to know it but also apply it (ie it might be in a context that you have not seen).
hi where did you get the number of moles from in the equations?
Riddhi Karani moles = mass/relative formula mass
Hey Sir, I'm able to balance all of these equations without the use of this method. Would I lose marks by balancing it from the formula given? Thanks
Yes, you would lose marks, if they tell you the mass in the question then it means they want you to work out the moles using the mass divided by Mᵣ to get the moles. If they don't give the mass then you should use the normal balancing method.
Hi, I heard you're making A-Level videos. is this true? if yes i would really be fascinated in watching your videos.
You are a legend!
i cant do this :(
this guy is a legend
can i ask where you find the moles or how you know how much moles there are?
You calculate the moles from the masses given. You should watch my two videos on this "Calculating moles of a compound" and "Calculating moles of an element". Let me know if you have any problems.
Thank you so much
1:14 , how is the realtive mass of chlorine 75 ? i dont get it
you're wonderful!!!
For the equation of moles shouldn’t it be RAM not MR ? Because in the miles video you said it was the ram not Rfm ?
We only use relative atomic mass if we're looking at an element. Relative formula mass refers to a compound (or a molecule). Remember that in the exam, the relative atomic masses are given in the questions.
Freesciencelessons OMG thank you so much ! Ur vids are amazing btw total life saver
What if we aren’t given the weight of the products
4:14 how do you work out the moles for aluminium sulfate
For this you need to do: Al: 27x2 = 54. Next you work out whats inside the bracket: S:32 O: 4x16 = 64, 64+32 = 96. 96 is whats inside the bracket, so you must times this by the outside number (3) 96x3 = 288. Finally you do 288+54 which is the total Mr for the aluminium sulfate, = 342. Using the equation you do 684(grams)/342 = 2.
What calculation did you do to get 4 moles from aluminium chloride? I dont understand.. Im getting decimal places in my calculation.
35.5×3=106.5
106.5+27=133.5
534÷133.5=4
It's simple really just listen to what he says.
At 4:20 I'm not sure how you got 4 moles FOR AlCl because no matter how many times i do it i get 2 moles. So, I did 137+(35.5 * 3) which gave me 243.5 so then i did 534/243.5 which gave me 2.193... and i rounded to 2 moles. Please tell me if I've done something wrong because i can't seem to figure out what i did.
Anika Achal 27+(35.5*3)=133.5 534/133.5= 4
Sir u should win the noble prize award
Why do you need to use this method when you can just balance the equation normally? Is it specifically needed for certain questions?
It's needed for certain questions where it's not obvious how to balance.
great video
omg helpppp, how do you know the subscribe for each element, I understand the calculation but without being given the subscript I don't know what I would do?
?
Can someone explain how to work out the relative formula mass im very confused about how you work it out i don't know why
Add up the relative atomic masses of the atoms in the molecule eg CaF2 = 40x1 + (19x2) = 78. Remember not to include any large number in front of the formula eg 2CaF2 still has a relative formula mass of 78.
"Hydrogen has a relative formula mass of 2". How did you work that out please?
H2 has two hydrogen atoms and each atom has a relative formula mass of 1. So 1x2 gives a relative formula mass of 2.
Thanks
So, in an exam, we won’t ever get decimals when dividing by the smallest number. Eg 5/2. You wouldn’t put 2.5 HCL right?
No, balancing involves whole numbers (except for combustion equations which can involve decimals). If you got 2.5 for one of the chemicals, then you would need to multiply every balancing number by 2 to make them all whole numbers.
Got my march mocks coming up. It's additional. What do I need to study unit 2 and what video playlist should I watch.
You need the unit 2 playlists. There's one for each topic or if you prefer, there's one for Biology, Chemistry and Physics.
Freesciencelessons thanks very much.
hi sir im sorry but how do i calculate the relative atomic mass of compounds?
You are given the relative atomic masses that you need for any moles question. However, you could be asked to calculate relative atomic mass from isotope data.
Calculating relative atomic mass is covered in this video (www.freesciencelessons.co.uk/gcse-chemistry-paper-1/atomic-structure-and-the-periodic-table-old/relative-atomic-mass/)
this guy deserves my grades
Will you be given the formula for number of moles in the exam?
No you need to learn it.
did not get the part where he came up for 2 moles for AL
54/27=2
Please do A-Level Videos!!!
4:18 please someone tell me how u find the mr of AI2(SO4)3
There are two aluminium atoms, each with an Ar of 27. There are three sulfur atoms, each with an Ar of 32. There are 12 oxygen atoms, each with an Ar of 16. Add all of that together to get 342.
If i don't have a whole number of moles do I have to get the ratio to a whole number
The ratio is determined only by the large numbers in the chemical equation not by the actual number of moles that you calculate.
Thanks!
hey i have a question, if i dont use moles for that type of question and just simply balance it out, would i lose marks?
The marks would come from the working out as well as the final answer.
Hello sir,I have a doubt. In 4:22 how did you get 6 because I got 7
round up the value
the way my teacher made it seem like university level chemistry but its literally so easy after watching this video wth