Electrons gained and lost during a redox reaction can be determined by examining the of the elements involved.

Answer is: oxidation numbers.

In oxido-reduction reaction, at least one element lose and one element gain electrons.

Oxidation reaction is increasing of oxidation number of atom, because element lost electrons in chemical reaction.

Reduction is lowering oxidation number because atom gain electrons.

For example, in oxidation-reduction reaction: 2H₂ + O₂ → 2H₂O; hydrogen is oxidized (change oxidation number from 0 to +1) and oxygen i s reduced (change oxidation number from 0 to -2).

Ithink that the use of creativity in the sciences entails that one produce something out of nothing or from another thing. with this, i think that the he wrote down his results as four parts of the atomic theory is the manifestation of the  creativity of john dalton.

Answerδh > 0explanationc₆h₆  (s)  → c₆h₆ (l)if you are changing it from a solid to a liquid, you are pretty much melting the solid. this requires heat energy. therefore, the reaction is endothermic (takes in energy); the system enthalpy increases as the reaction proceeds: δh > 0.