Chemistry Flashcards
Molar mass
the mass in grams of one mole of that substance.
solute
substance that is dissolved in the solution
solvent
substance in which another substance is dissolved, forming a solution.
Concentration
the number of moles of solute per unit volume of solution.
standard solution
solution of known concentration.
Electronegativity
measure of the tendency of an atom to attract a bonding pair of electrons.
covalent bond
the sharing of at least one pair of electrons by two atoms.
non-polar covalent (pure covalent)
an equal sharing of electrons.
polar covalent bond
unequal sharing of electrons leading to a dipole forming.
ionic bond
the transfer of electrons and subsequent electrostatic attraction.
Metallic bonding
between a positive kernel and a sea of delocalised electrons.
Intermolecular force
a weak force of attraction between molecules or between atoms of noble gases.
Intramolecular bond
the bond occurring between atoms within molecules.
The heat of reaction (AH)
the net change of chemical potential energy of the system.
Exothermic reactions
reactions which transfer potential energy into thermal energy.
Endothermic reactions
reactions which transfer thermal energy into potential energy.
Activation energy
the minimum energy required to start a chemical reaction.
catalyst
a substance that increases the rate of the reaction but remains unchanged at the end of the reaction.
Dipole-dipole forces
Forces between two polar molecules
Induced dipole forces or London forces
Forces between non-polar molecules
Hydrogen bonding
Forces between molecules in which hydrogen is covalently bonded to nitrogen, oxygen or fluorine,
activated complex
temporary transition state between the reactants and the products.
positive catalyst
a substance that increases the rate of a chemical reaction without itself undergoing a permanent change.
