Summary IEB physics, chemistry section summery

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, CHAPTER 12/

Quantitative chemistry
MOLE CONCEPT


Described as the SI unit for the amount of substance.

1 mol contains 6,021023 particles (Avogadro’s constant)

Molar mass is defined as the mass in grams of 1 mol of that substance
𝑚
n = 𝑀 1 mol is defined as the amount of substance that has the same number of
particles as 12g of the commonest isotope of c12
VOLUME OF GAS


1 Mol of gas occupies 22,4dm3 at STP
𝑉
n=𝑉 where Vm is always 22,4dm3
𝑚


CONCENTRATION OF SOLUTION



• Solution is a homogenous mixture of solute and solvent.
• Solute is a substance that is dissolved in the solution.
• Solvent is a substance in which another substance is dissolved. Forming a
solution.
𝑛
c=𝑣

STOICHIOMETRY

Yield is defined as a measure of the extent of a reaction, generally measured by
comparing the amount of product against amount of product possible.

𝑎𝑐𝑡𝑢𝑎𝑙 𝑦𝑖𝑒𝑙𝑑 100
% yield
𝑎𝑐𝑡𝑢𝑎𝑙 = 𝑡ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙
𝑦𝑖𝑒𝑙𝑑
% yield = 𝑡ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 × 100 oryield
or theoretical
× 100 𝑦𝑖𝑒𝑙𝑑 theoretical
= actualyield = actual
yield
100yield ×
× % 𝑦𝑖𝑒𝑙𝑑
𝑦𝑖𝑒𝑙𝑑 % 𝑦𝑖𝑒𝑙𝑑

Or
Or actual
actual yield
yield =
= theoretical yield 
theoretical yield  percentage
percentage yield
yield
𝑝𝑢𝑟𝑒 𝑚𝑎𝑠𝑠
%
% purity
purity =
𝑝𝑢𝑟𝑒 𝑚𝑎𝑠𝑠 × 100
= 𝑖𝑚𝑝𝑢𝑟𝑒 × 100
𝑖𝑚𝑝𝑢𝑟𝑒 𝑚𝑎𝑠𝑠
𝑚𝑎𝑠𝑠

N.B.
N.B. limiting
limiting reagent
reagent


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,CHAPTER 6

Chemical bonding
CHEMICAL REACTION


o Interactions between matter which generate substanes with new physical and
chemical properties
o The reacting substances are called reactants
o What is produced is called the products
o When a chemical reaction forms a chemical bond between 2 atoms or
molecules form, valence electrons are reaaranged to hold them together
o Lewis structures are used to represent unpaired electrons in elements
ELECTRONEGATIVITY



• The measure of how strongly an elements atoms attract a bonded pair of
electrons to themselves



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, • The higher the electronegativity the more time the electrons spend with that
atom when it bonds
• EN difference = 0, the bond is pure covalent
• EN difference = greater than/less than 0, bond is polar covalent
• EN difference = metal + non metal, bond is ionic

(difference in electronegativity = EN)

IONIC BONDING


▪ A transfer of electrons and subsequent electrostatic attraction
▪ Exists between an atom with a high electron affinity which gains an
electron and forms an anion to fill the valence shell (non-metal) and an
atom with a low electron affinity which loses electrons to fill the valence
shell and forms a cation (metal)
▪ Metal + non-metal, forms crystal lattice as positive and negative will
balance
▪ Involves transfer of electrons to form ions
Lewis structures:




COVALENT BONDING

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