AS.1 Basic Concepts Flashcards
Isotope
Atoms of the same element with the same number of protons and electrons but a different number of neutrons in the nucleus and therefore different masses
Relative atomic mass
weighted mean mass of one atom of an element compared to 1/12th of the mass of carbon-12
Relative isotopic mass
weighted mean mass of one isotope of an element compared to 1?12th of the mass of carbon-12
Strong acid
A proton donor that dissociates completely
Weak acid
A proton donor that dissociates partially
Monobasic acid
donates 1H+ per molecule e.g. HCl
Making a standard solution
A standard solution is one we know the concentration of
1) weigh out solute into weighing boat to 2dp
2)transfer all of solute into 250cm3 beaker. Use distilled water to rinse out weighing boat to ensure all of solute is transferred
3)add a small amount of distilled water to the beaker and stir with stirring rod to ensure all solute dissolves
4) transfer to 250cm3 volumetric flask
5) rinse beaker and stirring rod with distilled water and transfer washings to the volumetric flask
6) add distilled water until almost reached graduation line
7)carefully add water drop wise until bottom of meniscus is touching graduation line
8)calculate concentration to 3sf
Oxidation states - loss vs gain
OILRIG
Oxidation is loss of electrons
Reduction is gain of electrons
Silver oxidation state
+1
Zinc oxidation state
+2
Hydrogen oxidation state
+1 unless hydride which is -1
Oxygen oxidation state
-2 unless peroxide or bonded to F (
Halogen oxidation state
-1 unless Cl,Br,I bonded to O
Why isotopes have same chemical properties
Same number of electrons
Relative mass of an electron
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