What is the pressure in millimeters of mercury of 0.0135 mol of helium gas with a volume of 215 mL at a temperature of 45 ∘C?

What type of reaction fuels the processes seen here?

Which substance can be broken down by chemical means

4.25g sample of solid ammonium nitrate dissolves in 60.0g of water in a coffee-cup calorimeter, the temperature drops from 22.0 c to 16.9 c. assume that the specific heat of the solution is the same as that of pure water. calculate delta(h) (in kj/mol nh4no3) for the solution proces.