Commercial cold packs consist of solid ammonium nitrate and water. NH 4NO 3( s) absorbs 25.69 kJ of heat per mole dissolved in water. In a coffee-cup calorimeter, 3.40 g NH 4NO 3( s) is dissolved in 100.0 g of water at 21.0 °C. What is the final temperature of the solution? Assume that the solution has a specific heat capacity of 4.18 J/g•K.

The final temperature is

Explanation:

Generally number of moles is mathematically represented as

For the given compound NH 4NO 3( s)

      The molar mass would be =      

  Now substituting 14 for (molar mass of Nitrogen) , 1 for molar mass of hydrogen, 16 for molar mass of oxygen

    The molar mass of the compound  

  The mass of the compound dissolve is 3,40 g

Substituting into the above equation

Given in the question that  1 mole of NH 4NO 3( s)  absorbs 25.69kJ

                       then 0.0425 moles would absorb  x

 Now stating this mathematically

                  1 → 25.69 kJ

             0.0425 → x

cross-multiplying and making x the subject

Generally the heat energy absorbed  is mathematically denoted as

substituting  100.0 g  for m (mass of water) , 4.18 J /g.K for (Specific heat capacity)

Making the subject

               C

The initial temperature is 21.0°C

Since is been absorbed by NH 4NO 3 when it dissolves in water in mean that water losses energy so it temperature would reduce

       Therefore final temperature is

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