Calculate the energy of a photon emitted by a hydrogen atom when the electron falls from the n=14 energy level to the n=5 energy level.

Calculate the energy of a photon emitted by a hydrogen atom when the electron falls from the n=15 energy level to the n=5 energy level.

Which of the following when mixed with lithium sulfate (Li2SO4) will produce a precipitate?  SrI2 Fe(NO3)2 Pb(C2H2O2)2

A saline solution is prepared by mixing 21.384 g of NaCl into enough water to make 220.00 mL of solution.  325.00 mL of water is then added to the first solution.  What is the concentration of the final solution?

Phosphoric acid, H3PO4 is titrated with NaOH.  When the equation is balanced, what is the sum of all of the coefficients?

A researcher runs an experiment that produces 113.4 g of aluminum sulfate when adding 23.7 g of aluminum to excess sulfuric acid according the the following equations.  What is the percent yield of the reaction?  2Al(s) + 3H2SO4(aq) 

Which of the following statements is/are true?  The electron configuration of sulfur (S) is [Ne]3s23p4 The electron configuration of tin (Sn) is [Kr]5s24d105p2 The electron configuration of antimony (Sb) is [Kr]5s25d104d3

What is the molarity of acetate ions, C2H3O2–. if 3.41 g of magnesium acetate, Mg(C2H3O2)2, is in a 260.0 mL solution? 

Which of the following when mixed with potassium sulfate (K2SO4) will produce a precipitate?  Cu(NO3)2 Pb(ClO4)2 BaBr2

Which of the following statements is/are correct? (3, 0, 0, -) is an electron set for an electron in a 3s orbital (3, 3, 0, -) is a valid set of quantum numbers (2, 1, -1, +) is a valid set of quantum numbers