Answer: D. 19.9 g hydrogen remains.
Explanation:
To calculate the moles, we use the equation:
a) moles of
b) moles of
According to stoichiometry :
1 mole of require 1 mole of
Thus 0.0787 moles of require=
of
Thus is the limiting reagent as it limits the formation of product and
acts as the excess reagent. (10.0-0.0787)= 9.92 moles of
are left unreacted.
Mass of
Thus 19.9 g of remains unreacted.
Answer to this is Radioactive isotopes.
Isotopes are the species of the same element having different atomic masses that means the number of protons remains the same but number of neutrons do differ. For example and
are the two isotopes of Hydrogen (
).
Radioactive isotopes are the isotopes which release some kind of energy in the form of alpha particles, beta particles or gamma radiation. Examples of each of the decay processes are :
Alpha Decay: In this decay one alpha particle having atomic mass 4 and atomic number 2 or we can say a He molecule will come out.
Beta Decay: In this decay a particle is emitted increasing the atomic number of the reactant by 1 unit.
Gamma Radiation: In this type of reaction only radiation is emitted out which does not change the original molecule.