Hydrogen Emission Spectrum Lab

Question

So I've recently did a hydrogen emission spectrum lab.

 

These were the four wavelengths I got:

 

Red         675 nm

Green      570 nm

Blue        460 nm

Purple      425 nm

 

These are the accepted wavelengths:

Red          645 nm

Green       486 nm

Blue         433 nm

Purple       410 nm

 

From that I need to find out the ΔE , n_i and the percentage error.

Answer 1

Get the theoretical E using the Rydberg formula for the Balmer (visible) hydrogen lines.  Get ΔE from the difference of your measured E and the theoretical E.

 

Theoretical E:

 

E = hc/λ

 

1/λ = R(1/2² - 1/n_i²)   [Electron falls from n = n_i to n = 2, which is a visible line.]

 

E = hcR(1/2² - 1/n_i²),

 

n_i = 3, 4, 5, ...

 

You can find h, c, and R in your chemistry book, in appropriate units.

 

Measured E:

 

E = hc/λ  [Use here your measured wavelengths]