What is the percent of Nitrogen in NH3?

In salt water solution,the salt is the blank

In a heat engine of 1000 j of heat enters the system and the piston does 500 j of work what is the final internal energy of the system if the inital energy was 2000 j we have to do all of these down here 1)write the equation 2)list out your know variables 3)plug the numbers into the equations 4)solve 5)write your solution statemtn that includes inital energuy and final energuy added

An engineer wishes to design a container that will hold 12.0 mol of ethane at a pressure no greater than 5.00x10*2 kpa and a temperature of 52.0 degrees celsius. what is the minimum volume the container can have?