how do i solve?

Question

What is the energy of 4.43 x 10^–3 moles of 1.23 nm X-ray photons?  kJ

Answer 1

Similar to your previous question.

E = hc/λ

convert 1.23 nm to meters (1 m = 1x10⁹ nm) = λ

h = 6.626x10-34 J-sec

c = 3x108 m/sec

Solve for E in J

This is the E of one photon

Multiply by 4.43x10^-3 to get energy of this many photons

If you want kJ, divide by 1000