[inferno101]

i have a couple questions that i cant solve and i would like to check some answers
 A 10. L sample of an unknown gas at STP was burned completely in oxygen, and the products were isolated and cooled to STP. The products were carbon dioxide (20. L of gas) and water (16 g of liquid). What is the molecular formula of the unknown gas?
i got c2h4 is that right

How many of the first twenty elements in the periodic table are diatomic gases at room temperature and 1 atm pressure? i got 5

A metal has an electron binding energy of 338. kJ/mol What is the minimum frequency (in Hz) , for the onset of the photoelectric effect?  i got 8.4592e14

How many photons of light having a wavelength of 656 nm are necessary to provide 1.0 J of energy?
i got ) 3.0 x 10-19

Determine which H atom transition (ninitial,nfinal) was responsible for the emission of a photon with a frequency of 6.17 x 1014 Hz. i got (2,4)   

What is the angular momentum quantum number for a subshell containing nine orbitals? im not sure about this one

The noble gases (group 18 in the periodic table) have how many unpaired electrons in their ground state configurations? i got 0

Which of the following statements about UV radiation is/are FALSE? (Select all that apply).
a.    UV B radiation covers a longer wavelength spectrum than UV A radiation.
   b.    UV B radiation has sufficient energy to break any covalent bond.
   c.    UV B radiation covers a frequency range of approximately 9.52 x 1014 s-1 to 1.07 x 1015 s-1.
   d.    UV C radiation is lower energy radiation than UV B radiation.
   e.    UV A radiation has a frequency greater than X-radiation.   
not sure about this one