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1.30 Percentage yield
David Fowkes
IGCSE Chemistry
A 50% yield In this section we consider how much product is formed by a chemical reaction . Some reaction processes are not very efficient and only a small proportion of the reactants are actually turned into the products.  The yield of a chemical reaction is the amount of product obtained.  It is usually expressed as a perce...
The uncertain location of electrons
David Fowkes
Chemistry A Level
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1.10 Separation techniques
David Fowkes
IGCSE Chemistry
 Students should: 1.10 describe these experimental techniques for the separation of mixtures: simple distillation fractional distillation filtration crystallisation paper chromatography Each technique listed here is a method which can be used for the separation of mixtures of substances. Work through each method in turn . 1.10 Simple distillat...
1.26 - 1.28 Moles and mountains
David Fowkes
IGCSE Chemistry
Relative masses allow chemists to "count out" atoms and molecules so they can ensure that the appropriate amounts of substances are reacted.
1.28 Moles and mountains
David Fowkes
Uncategorized
Calculating the number of moles knowing the mass and the Ar ( mass of one mole)   1.28 Calculating moles The following masses of elements all contain one mole of atoms: 12.0 g Carbon, 32.1 g Sulphur, 14 g Nitrogen, 24.3 g Magnesium.  So if you have 24 g carbon you have 24/12 = 2 moles carbon atoms. Likewise if you have 1.4 g nitrogen you have 1.4/14 = 0.1 moles nitrogen atoms.  Rearrangin...
1.27 The Mole
David Fowkes
Uncategorized
A mole of rice grains would form a huge mountain of rice with enough rice to feed the world's current population for the next 6088978 years!  1.27 What is a mole?  Students should: 1.27 know that the mole (mol) is the unit for the amount of a substance 1.28 understand how to carry out calculations involving amount of substance, relativeatomic mass (Ar) and relative formula mass (Mr) A mole (mol) is the quantity of anything that has the same number of particles as there are ato...
1.26 Formula masses
David Fowkes
IGCSE Chemistry
Large numbers of coins can be counted by measuring their mass  1.26 "Counting" by measuring mass Sometimes chemists need to "count" out a specific number of atoms, ions or molecules of a substance. Atoms are very very small - too small to see. It is therefore impossible to measure them out by counting individually.  Instead we "count" them out by measuring their mass - much like ...
Copy of Copy of 1.26 - 1.28 Moles and mountains
David Fowkes
IGCSE Chemistry
Relative masses allow chemists to "count out" atoms and molecules so they can ensure that the appropriate amounts of substances are reacted.
Rusting rates
David Fowkes
IGCSE Chemistry
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Effect of particle size on the rate of rusting
David Fowkes
IGCSE Chemistry
​To test the effect of particle size on the rate of oxidation we prepared three samples of steel wool each with different levels of coarseness (shown left). The test tube on the left contains the fine steel wool while the one in the middle contains the medium conciseness steel wool and the test tube on the right contains the coarsest stee...

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