question archive Trial 1 Trial 2 Trial 3 Mass of water (g) 50
Trial 1 Trial 2 Trial 3 Mass of water (g) 50
Subject:ChemistryPrice: Bought3
Trial 1 Trial 2 Trial 3 Mass of water (g) 50.08 g 50.07g 50.00g Mass of NH43 10.09g 10.03g 10.07g
NO(g)
Moles of NH4NO3 (g)
0.126
0.125
0.126
Initial temperature (°C)
23.8 °C
23.8 °C
23.8 °C
Minimum temperature (°C)
6.5 °C
6.5 °C
6.4 °C
DT (°C)
-17.3
-17.3
-17.4
DHsurr (J)
-3684
-3684
-3679
DHsys (J)
3684
3684
3679
DHrxn (kJ per mole)
24.82
24.98
24.78
1) Is the reaction endothermic or exothermic? How can you know this in terms of the physical experimental observations, before doing any calculations?
2) Is the reaction accompanied by an increase or decrease in entropy? Explain this in terms of what happens physically in the experiment. What is the sign of DSrxn?
3) Considering the signs for DHrxn and DSrxn, is the spontaneity of the reaction driven by the change in enthalpy or entropy? (Consider DGrxn). Explain your choice.
4) What should be the sign of DS for a precipitation reaction? Explain your answer.
5) For a spontaneous precipitation reaction, what then must be the sign of DH? Explain.
