How much heat is evolved when 1260 g of water condenses to a liquid at 100.°c?

Moles H2O = 1233 g/ 18 g/mol=68.5 68.5 x 40.7 =2788 kJ

To solve this you need the value for ΔHvap for water, which is a constant that tells you how much energy is used/released when water changes it's physical state from vapour to liquid, or liquid to vapor. 

There is one s orbital, and there are three p orbitals, five d orbitals, and seven f orbitals. thus, the answer is b. do not confuse the number of orbitals in a subshell with the number of electrons the subshell can hold. each orbital can hold two electrons, so the capacity of an nf subshell is 14 electrons.