Summary
Summary AQA Chemistry- Amount of Substances Notes
- Institution
- AQA
Detailed and highlighted notes on Amount of Substances
[Show more]
Seller
Follow
Content preview
Amount of SubstanceRelative Atomic Mass→ average mass of one atom relative to 1/12th of the mass of
one atom of C-12
Empirical Formula→ simplest integer ratio of atoms in each element in a compound
Molecular Formua→ actual number of atoms of each element in a compound
How many moles of X atoms are present in p moles of XnYm?⇒ n * p= number of moles
Empirical and Molecular Formula⇒
1. Divide each mass (or % mass) by the atomic mass of the element
2. For each of the answers from (1) divide by the smallest one of those
3. Turn the ratio into whole numbers which give the empirical formula
4. Find the Mr of the empirical formula
5. Divide the Mr of the molecular formula by the empirical to find the multiple
6. Multiply the empirical formula by your whole number answer in (5)
Water of Crystalisation⇒
Find x from M·xH2O:
(1) Mass of beaker (g) b
(2) Mass of hydrated salt in w+s+b
beaker (g)
(3) Mass of anhydrous salt s+b
after heating in beaker (g)
Mass of hydrated salt= (2) - (1) (w+s+b) - b=w+s
Mass of water lost= (2) - (3) (w+s+b) - (s+b)=w
Mass of anhydrous salt= (3) - (1) (s+b) - b=s
1. Find the moles of M (anhydrous salt)
2. Moles of M·xH2O=moles of M
3. Find Mr of M·xH2O by dividing the mass of the hydrated salt by its moles
4. Solve for x
Dilution⇒ Original concentration * (original volume/total volume)
Ideal Gas Equation⇒
P(Pa) * V(m3) = n * R(8.31J/K/mol) * T(K) → must state
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 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 cironvisahar. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £7.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
73918 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now