Amount of substance GapFill

No atoms are created or destroyed in a reaction. This is called  particle theoryentropyrelative atomic massatom economyconservation of massAvogadro's rule. Chemical reactions are represented using symbols to represent  molesvolumesconcentrationsmasseselectronselements, with numbers in front of them to  balanceexpandtime-stampsequenceprioritisecombine the equation.

The relative formula mass of a chemical can be calculated by adding together the  ratioconcentrationschargesatomic numbersrelative atomic massesvolumes of the atoms. In a balanced equation, the relative formula masses of the products equals that of the  air or solutionmetalstheoretical massreactantsmass lostprotons. If a reaction ever seems to lose or gain mass it is because  an unreactivea gaseousa radioactivean unstablean isotopica side product or reactant is involved, whose mass does not get measured.  EstimationUncertaintyCorrectnessReliabilityDoubtProbability is a way of describing the accuracy of a measurement.