Ch. 11 & 6  light & moles                    test [70 points]

Show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer. 

1. In regards to light,  [20 points]

a.What is the energy of light if it has a frequency of 3.5 M Hz ?

b.  What is the wavelength of light (in cm) if it has an energy of 2.5 * 10 -19 Joules ?

2. In regards to the hydrogen line spectrum, where the atom emits (or absorbs) blue and green light, sketch the relative electron energy levels in the atom to describe the ___ spectrum.  Clearly identify the transition for blue versus green light.  [20 points]

a.  Emission                                                               b.  absorbance

 

3. solve  [30 points]

a.  0.00150 micromole sulfur dioxide = __ g sulfur dioxide

b.  1.05 * 10 20 C8H10N4O2 (caffeine)  molecules =  ___ mg caffeine

c.  0.0666 nanomole C3H8  =  __ C3H8 molecules