definitions Flashcards
Whats the relative atomic mass?
The weighted mean mass of an atom of an element compared to 1/12th of the mass of carbon-12
whats the relative isotopic mass?
The mass of an isotope compared to 1/12th of the mass of an atom of carbon-12
Whats the enthalpy change of formation?
Enthalpy change when 1 mole of compound is formed from its elements
Whats enthalpy change of atomisation of an element?
Enthalpy change when 1 mole of gaseous atoms is formed from an elements.
e.g. 1/2Cl2 to Cl2
Whats enthalpy change of atomisation of a compound?
enthalpy change when 1 mole of a compound is converted to gasesous atoms.
solid to gas
What is the first electron affinity?
the energy needed to change 1 mole of gaseous atoms into 1 mol of gaseous 1- ions.
O + e- -> O-
What is lattice enthalpy?
the enthalpy change when 1 mol of an ionic solid compound is formed from its gaseous ions
What is the enthalpy change of hydration?
Enthalpy change when 1 mol of gaseous ions dissolves in water to form aqueous ions
What is the enthalpy change of solution?
enthalpy change when 1 mole of solute is dissolved in solvent.
What does entropy mean?
The measure of the dispersal of energy within a system
What is meant by isotopes?
Atoms of the same element with a different number of neutrons but the same number of protons and electrons
Why do isotopes have the same chemical properties?
They have the same number of electrons in the outer shell.
How is a salt formed?
When a hydrogen ion of an acid is replaced by a metal ion
What is the colour change when chlorine gas is bubbled through potassium iodide?
brown because the iodide ions are oxidised to iodine
what is meant by electronegativity?
the ability of a covalent bond in an atom to attract a pair of electrons
