Ch. 11.2 light & ch. 6 moles                            50 points (5 ec)                                     chemistry

In problems involving any calculation, 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.

If you use Mathematica, state that you used it, write the command, and answer.  Scoring will tend to be “all or none” with minimal / no points for any error in your code.

1. A photon of light has a wavelength of 125 micrometers; what is it’s frequency ?  [5 points; weekly quiz problem]

2.  A photon of light has a wavelength of 125 nanometer; what is it’s energy ?  [10 points; weekly quiz problem]

3. Solve.  [15 points]

a.  25 millimole of copper (II) nitrate  =  __  g copper (II) nitrate, Cu(NO3)2

b. 75 g sodium sulfide  =  __  moles of sodium sulfide, Na2S

c.  125 *  10 12 molecules of glucose =  __  g of glucose

4.  What is the empirical formula of a sample of tin chloride with 37% chlorine ?  [10 points]

5. What is the % composition of all atoms in calcium phosphate, Ca3(PO4)2 ?  [15 points]