Calculate the number of photons emitted form the red line `(6560A^@)` of hydrogen of energy 0.1 Joule

Calculate the number of molecules in 1 gm water.

Calculate the wavelength of a photon of energy 10 eV.

Calculate the number of photons if 6.62J of radiation energy of frequency of 10^12H_Z .

Calculate the number of molecules in 0.1 mole of SO_2 .

Calculate the amount of chlorine required to completely react with 4.56 g of hydrogen (h_2) to yield hydrochloric acid (HCl) ? Also calculate the amount of HCl formed.