5.39 g of urea (molar mass 60.06 g/mol) dissolves in 35.00 g of water at 20.0 degrees C in a Styrofoam cup calorimeter. The temperature of the solution decreased to 12.0 degrees C. The specific heat of the solution is 4.18J/g o C)

i) Calculate the magnitude of heat energy in kJ during this change.

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.

there are two significant figures.