At standard pressure, ammonia melts at 195 k and boils at 240 k. if a sample of ammonia at standard pressure is cooled from 200 k down to absolute zero, what physical constants are needed to calculate the change in enthalpy? i) the heat capacity of ammonia(s) ii) the heat capacity of ammonia(ℓ) iii) the heat capacity of ammonia(g) iv) the enthalpy of fusion of ammonia v) the enthalpy of vaporization of ammoni

I) the heat capacity of ammonia(s)

II) the heat capacity of ammonia(ℓ)

IV) the enthalpy of fusion of ammonia

Explanation:

Initially, ammonia at 200 K is liquid. To calculate the change of enthalpy from 200 K to 195 K (melting point) we need to know the heat capacity of ammonia(ℓ).

At 195, ammonia is in the transition from liquid to solid (solidification). To calculate the change of enthalpy in that process we need to know the enthalpy of solidification of ammonia, which has the same value but opposite sign to the enthalpy of fusion of ammonia.

From 195 K to 0 K, ammonia is solid. To calculate the change of enthalpy in that process we need to know the heat capacity of ammonia(s).

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

there are no statements provided but here is why:

sulfur belongs to group 16 because it can be found in nature whether it is in a free or combined state.

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