Calculation of half-life

Which of the following describes a situation where competition between producers exists

Which symbol can be used to indicate the pressure at which a chemical reaction is carried out? 25°c 2 atm pa

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.