Asample of ammonia liberates 5.66 kj of heat as it solidifies at its melting point . what is the mass of the sample?

The correct answer for the question that is being presented above is this one: "16.728 g."

Given that 
ΔHsolid = -5.66 kJ/mol.
This means that 5.66 kJ of heat is released when 1 mole of NH3 solidifies 

When 5.57 kJ of heat is released
amount of NH3 solidifies = 5.57/5.66 = 0.984 moles 

molar mass of NH3 = 17 g/mole 
1 mole of NH3 = 17 g 
So, 0.984 moles of NH3 = 17 X 0.984 = 16.728 g

The water cycle increase the water content in the earth atmosphere