Definitions - Module 2 Flashcards
Atomic number
The number of protond/electons in an atom
Isotope
Atoms of the same element with different numbers of neutrons and masses
Mass number
number of protons + number of neutrons
Relative atomic mass
The weighted mean mass of an element relative to 1/12th the mass of an atom of Carbon-12
Relative isotopic mass
The mass of an isotope relative to 1/12th the mass of an atom of Carbon-12
Ion
Is a charged atom
Cation
Positive ion (fewer electrons than protons)
Anion
Negative ion (more electrons than protons)
Aqueous
Dissolved in water
1 mole
the amount of substance that contains Avogadro constant (6.02x10^23) particles
Avogadro constant
6.02x10^23mol^-1
The number of partilces in each mole of carbon-12
Molar mass
mass in grams in each mole of the substane (gmol^-1)
Molecular formulae
the number of atoms of each element in a molecule
Empirical formulae
the simplest whole number ration of atoms of each element in a compound
Relative formula mass
compares the mass of a formula unit with the mass of an atom of carbon-12
Relative molecular mass
compares the mass of a molecule with the mass of an atom of carbon-12
Assumptions of the ideal gas equation
1) random motion
2) elastic collisions
3) negligible size
4) no intermolecular forces
Stoichiometry
the ration of the amount in moles of each substance in a balanced symbol equation
Percentage yield
actual yield/predicted yield x100
Limiting reagent
The reactant that isnt in excess and will be completely used up first causing the reaction to stop
Atom economy
Mr of desired products/Mr of all products x100
A strong acid
completely ionises in water (releases all of it H+ ions)
A weak acid
Partially ionises in water (releases a small proportion of its available H+ ions)
Titrations can be used for
1) finding the concentraion of a solution
2) Identifying unknown chemicals
3) finding the purity og a substance
