A 20 kg mass is placed 0.75 m on the left side from the pivo…

A 20 kg mass is placed 0.75 m on the left side from the pivot of a 4 m long beam. Another mass of 30 kg is placed on the right side of the beam at distance 1.5 m from the pivot. If the beam is balanced by placing a third mass on the left side at distance 1.5 m, what is the mass?

Iodine-131 is one of the most important isotopes used in the…

Iodine-131 is one of the most important isotopes used in the diagnosis of thyroid cancer. One atom has a mass of [x] amu. Calculate the binding energy per atom in MeV.   1 amu= 931.5 MeV.   Mass of a proton is 1.007825 amu while mass of a neutron is 1.008655 amu. Enter a positive number to 1 decimal place.

Would a 0.1 M solution of the salt NH4CN be acidic, basic or…

Would a 0.1 M solution of the salt NH4CN be acidic, basic or neutral?   Kb of NH3= 1.8 × 10-5 and Ka of HCN = 4.9 × 10-10.  Explain your answer with appropriate Ka and Kb calculations.  No need to calculate the actual pH of the salt unless you want to prove to yourself. Show your work either here or on the scratch sheet and upload under Exam III work.  No need to do both places.