Answer:
The frequency of photon is 0.75×10¹⁵ s⁻¹.
Explanation:
Given data:
Energy of photon = 5×10⁻¹⁹ J
Frequency of photon = ?
Solution:
Formula;
E = hf
h = planck's constant = 6.63×10⁻³⁴ Js
5×10⁻¹⁹ J = 6.63×10⁻³⁴ Js ×f
f = 5×10⁻¹⁹ J / 6.63×10⁻³⁴ Js
f = 0.75×10¹⁵ s⁻¹
The frequency of photon is 0.75×10¹⁵ s⁻¹.
Answer:
ΔH°rxn = -47 kJ
Explanation:
Using Hess´s law for the reaction:
3 Fe2O3(s) + CO(g) → 2 Fe3O4(s) + CO2(g) ,
the ΔH°rxn will be given by the expression:
ΔH°rxn kJ = 2ΔHºf(Fe3O4) + ΔHºf(CO2) - ( 3ΔHºf(Fe2O3) + ΔHºf(CO) )
= 2(-1118) + (-394) - ( 3( -824 ) + ( -111 ) )
= - 47 kJ
