# Why is Specific heat of Ammonia higher than water?

The specific heat of water is lower than that of $$\ce{NH3}$$, but why?

$$\ce{H2O}$$ forms more hydrogen bonds if I am right, besides there's more electronegativity for Oxygen.

But still, $$\ce{NH3}$$ has higher Specific heat. I found this link saying $$\ce{NH3}$$ has lower molar mass, but its just by one gram so it shouldn't be having much effect right?

• chemistry.stackexchange.com/questions/26651/…. May refer to the link for all clarification. Jan 14 '21 at 8:52
• $\ce{H20}\$ is unknown. You may mean $\ce{H2O}$. Be aware chemists may be quite sensitive for O vs 0 replacement in chemical formulas. Jan 14 '21 at 9:33
• Consider the effect of lower molar mass and of counts of vibration degrees of freedom on the specific heat capacity. Jan 14 '21 at 9:40

1. The isobaric specific heat of ammonia (gas) is 2.1636 kJ/kgK at 1 atmosphere and temperature = 26.9 C. https://www.engineeringtoolbox.com/ammonia-heat-capacity-specific-temperature-pressure-Cp-Cv-d_2016.html At -33.6 C (boiling point of $$NH_3$$ at 1 atm), the specific heat of $$NH_3$$ gas is 2.2946 kJ/kgK, not much different from the gas at 26.9 C; however, for liquid $$NH_3$$ at 1 atm and -33.6 C, the specific heat is 4.4464 kJ/kgK, a large increase from the gas at that temperature.
2. Liquid water has one of the highest specific heats among common substances, about 4182 J/(K kg) at 20 °C https://en.wikipedia.org/wiki/Specific_heat_capacity At 100 C, liquid water has a specific heat of 4.2157 kJ/kgK (implied pressure = 1 atm). Again, not much difference because of temperature. https://www.engineeringtoolbox.com/specific-heat-capacity-water-d_660.html Now we find water vapor data in a different place: https://www.engineeringtoolbox.com/water-vapor-d_979.html where gaseous $$H_2O$$ at 216 F (102.2 C) has a specific heat of 1.890 kJ/kgK, a large drop, even bigger than in the ammonia system.