Determine the molecular geometry of KrO2F2 (Kr is the central atom, and all the others are terminal atoms).

A balloon contains 0.86 mol N2, 0.22 mol O2, 0.061 mol He and 0.049 mol H2. Calculate the mole fraction of O2.   

Calculate the molarity of 40.0 grams of NaOH dissolved in 200 mL solution.

The 227Ra2+ ion  contains how many neutrons (n) and electrons (e)?

The phosphorus atom in PCl3 would be expected to have a ______________.

What number of moles of NaOH is needed to completely neutralize 100 mL of 0.40 M HNO3? (molar ratio for this reaction is 1:1)

Which isotope has 36 electrons in an atom? 

Consider the reaction: 2 N2(g) + 5 O2(g) ——->  2 N2O5(g) How many grams of O2 are required to react with 70 grams of N2?

What is the temperature, in oC, of a sample containing 11 g of CO­2(g) in a 20 L container at a pressure of 0.30 atm?

What is the method of each of these disciplines?