How many joules of heat are evolved by a reaction in a calorimeter where the temperature of the bomb and the water increases from 19.50°c to 22.83°c? the bomb has a heat capacity of 650.0 j/°c, and the calorimeter contains 320.0 g of water.

The number  of joules  of heat  that are evolved by  a reaction  in a  calorimeter  is  692,640  joules

calculation

Heat= MCΔT   where,

 M(mass)=  320.0  g

C ( specific  heat  capacity)= 650.0  j/c

  ΔT ( change in temperature) = 22.83-19.50= 3.33  C

heat is therefore=  320.0 g  x 650 j/c   x 3.33 c =692,640  joules

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.