Compound X absorbs photons with a wavelength of 179.3 nm. What is the increase in energy of a 0.115 M solution of compound X in which a mole of photons are absorbed

Explanation:

 one mole of photon will contain  

6.02 x 10²³ no of photons

energy of one photon = h x f

= h c / λ

h is plank's constant , c is velocity of light and λ is wavelength

= 6.6 x 10⁻³⁴ x 3 x 10⁸ / 179.3 x 10⁻⁹

= .11 x 10⁻¹⁷ J

energy of one mole of photon

= 6.02 x 10²³ x .11 x 10⁻¹⁷

= .6622 x 10⁶ J

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.