A chemist wait out 87.1 g of sodium. Calculate the number of moles of sodium she weighed out. Round your answer to three significant digits

What is the molar mass of a gas that has density of 2.054 g/l

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

Oil rich countries in the middle east cover about 4% of earths total land area but prossess about 48% of the worlds known oil reserves what is the main reason for high concentration of reserves in this part of the world