When an atom in a reactant gains electrons, what happens to its oxidation number?
a).its oxidation number decreases.
b).its oxidation number doubles.
c).its oxidation number increases.
d).its oxidation number increases by one.
e).its oxidation number stays the same.

Acalorimeter is to be calibrated: 51.203 g of water at 55.2 degree c is added to a calorimeter containing 49.783 g of water at 23.5c. after stirring and waiting for the system to equilibrate, the final temperature reached is 37.6 degree c. specific heat capacity of water (s = 4.18 j/g∙degree c). calculate the calorimeter constant. (smδt)warm water = -[(smδt)cold water + (calorimeterδtcold water)]