CHM-1-Stoichiometry Flashcards
Composition of Air
78% Nitrogen
21% Oxygen
1% Other Gases
What is Stoichiometry?
The calculation of the specific quantities of reactants and products in a reaction.
What is an empirical formula?
The simplest whole number ratio for a compound. E.g Hydrogen Peroxide (1:1 Ratio) would be ‘HO’
What is a molecular formula?
The exact number of the different atoms making up a molecule. E.g Hydrogen Peroxide (1:1 Ratio) would be H2O2.
What is the definition of Avagadro’s number?
The number of atoms in 12 grams of carbon’s most common isotope.
What is the value of Avagadro’s number?
6.02 x 10^23
A mole of atoms/molecules contains…
an Avagadro number of these particles.
What is the gram-atomic weight (GAW)?
The weight in grams of a mole of atoms of a given element.
What is the gram-molecular weight (GMW)?
The weight in grams of mole of molecules of a given compound.
Formula to calculate the number of moles for an element.
Moles = (Weight of sample [g] / GAW)
Formula to calculate the number of moles for a compound.
Moles = (Weight of sample [g] / GMW)
The GAW of any element is equal to…
Its atomic weight
What is amu?
Atomic Weight
What is a reactant?
A compound which initially combines or reacts in a chemical reaction
What is the number before compounds in a chemical equation and what do they represent?
The stoichiometric coefficient - The relative number of moles in a compound
The law of conservation of mass
The number of atoms of a given element remains constant during the process of a chemical reaction.
The g/mol value of an element is the same value as the…
Atomic Mass
What is OILRIG?
When talking about one or more electrons:
Oxidation Is Loss
Reduction Is Gain
Give the oxidation numbers for:
Hydrogen Oxygen Alkali Metals Alkaline Earth Metals Aluminium
\+1 -2 \+1 \+2 \+3
Oxidation number for Group VIIA elements E.g Chlorine.
-1 However, it becomes +1 when combined with an element with higher electronegativity.
If an element causes another element to have a decreased oxidation number in a reaction, it is known as…
A reducing agent
What can be used as reducing agents?
Metals
2 common oxidising agents
Halogens
Ozone (O3)
