Summary
Summary AS Unit F321 - Atoms, Bonds and Groups
- Course
- Institution
A level notes on unit 1 of OCR A Chemistry, made by an A student
[Show more]
Seller
Follow
neevebishop04
Content preview
RELATIVE ATOMIC MASSWe can use a mass spectrometer to identify the number of isotopes + abundance of
isotopes. From this we can calculate Ar (relative atomic mass).
Ar = (Mass of isotope x abundance) + (Mass of isotope x abundance) / 100
E.G. (28x92.21) + (29x4.7) + (30x3.09) / 100 = 28.1
204.37 = (20.3 x Y) + (20.5 x (100-y) / 100
1. Multiple by 100
20437 = (203 x Y) + (205 x (100-Y)
2. Multiply by the 100 in the bracket
20437 = 203y + 20500 - 205y
3. Minus the 20,500 from the original number
-63 = 203y - 205y
4. Minus the numbers
-63 = -2y
5. Divide by the y (in this case, 2)
31.5 = Y
Relative atomic mass = The weighted mean mass of an atom of an element compared
1/12th of the mass of carbon12.
Relative isotopic mass = The mass of one isotope compared to one twelfth of the
mass of carbon12.
IONIC EQUATIONS
Spectator ions = A particle that hasn’t changed from left to right.
Ignore spectator ions in ionic equations
ONLY SPLIT IF AQ
E.G. BaCl2 (aq) + 2AgNO3 (aq) -> Ba(NO3)2 (aq) + 2AgCl (s)
Ba 2+ , 2Cl - , 2Ag +, 2NO3-, -> Ba2+ , 2NO3-
2Cl- (aq) + 2Ag(aq) -> 2AgCl (s)
, STOICHIOMETRY
= Mole ratio
E.G. Calculate the mass of aluminum needed to react with 150g of Chlorine.
2Al + 3Cl2 -> 2AlCl3
n Cl2 = m/Mr - 150/71 = 2.11268 moles
Cl2 : Al
3 : 2
n Al = n x Mr = 1.40845 x 27 = 38.0g
MOLES & GASES
Gases take up a specific volume of space at RTP (room temperature & pressure, 25
degrees & 100KPa).
One mole of gas at RTP has a volume of 24dm3.
/
cm3 -> dm3 -> m3
<- <-
x 1000 x 1000
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller neevebishop04. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $8.38. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67474 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now