Ammonia is written NH₃. With school atomic masses the molar mass is 17 g/mol. Ammonia is a trigonal pyramidal molecule with a lone pair on nitrogen, which makes it a weak base and good ligand.
H₂O
WaterNH₃
AmmoniaCO₂
Carbon DioxideH₂O₂
Hydrogen PeroxideSO₂
Sulfur DioxideNO₂
Nitrogen DioxideHCl
Hydrochloric AcidH₂SO₄
Sulfuric AcidHNO₃
Nitric AcidCH₄
MethaneC₂H₆
EthaneC₃H₈
PropaneC₄H₁₀
ButaneC₂H₄
EthyleneC₂H₂
AcetyleneC₆H₆
BenzeneC₇H₈
TolueneC₁₀H₈
NaphthaleneC₆H₁₂
CyclohexaneCH₃OH
MethanolC₂H₅OH
EthanolCH₃COOH
Acetic AcidHCHO
FormaldehydeCH₃COCH₃
AcetoneC₄H₁₀O
Diethyl EtherC₂H₇N
EthylamineC₂H₅NO
AcetamideC₆H₁₂O₆
GlucoseC₆H₁₂O₆
FructoseC₁₂H₂₂O₁₁
SucroseCO(NH₂)₂
UreaC₂₇H₄₆O
CholesterolC₉H₈O₄
AspirinC₈H₉NO₂
AcetaminophenC₁₃H₁₈O₂
IbuprofenC₈H₁₀N₄O₂
CaffeineC₆H₆N₂O
NicotinamideC₆H₈O₆
Ascorbic AcidC₁₆H₁₈N₂O₄S
Penicillin GC₂H₆O₂
Ethylene GlycolC₈H₈
StyreneC₂H₃Cl
Vinyl ChlorideC₃H₅NO
AcrylamideC₆H₁₁NO
CaprolactamLiCl
Lithium chlorideNa₂O
Sodium oxideNaCl
Sodium chlorideMgF₂
Magnesium fluorideAlCl₃
Aluminum chlorideCaO
Calcium oxideCaC₂
Calcium carbideKNO₃
Potassium nitrateMg₃(PO₄)₂
Magnesium phosphateAl₂(SO₄)₃
Aluminum sulfateMg(OH)₂
Magnesium hydroxideNH₄Cl
Ammonium chlorideNH₄OH
Ammonium hydroxideCuO
Copper(II) oxideCu₂O
Copper(I) oxideFeSO₄
Iron(II) sulfateFe₂(SO₄)₃
Iron(III) sulfatePbCO₃
Lead(II) carbonateMgO
Magnesium oxideAl₂S₃
Aluminum sulfideLiF
Lithium fluoride(NH₄)₂S
Ammonium sulfideKF
Potassium fluorideNiCl₂
Nickel(II) chlorideKCN
Potassium cyanideCH₃COONa
Sodium acetateCaCO₃
Calcium carbonateNa₃P
Sodium phosphideBeBr₂
Beryllium bromideFeO
Iron(II) oxideHg₂Cl₂
Mercury(I) chlorideHg(NO₃)₂
Mercury(II) nitrateCH₃COOCu
Copper(I) acetateSiO₂
Silicon dioxideP₄O₁₀
Tetraphosphorus decaoxideN₂O₅
Dinitrogen pentoxideCO
Carbon monoxideHF
Hydrogen fluoridePCl₅
Phosphorus pentachlorideCF₄
Carbon tetrafluorideSF₆
Sulfur hexafluorideNBr₃
Nitrogen tribromideN₂O
Dinitrogen monoxideN₂O₃
Dinitrogen trioxideCS₂
Carbon disulfideCl₂O₇
Dichlorine heptoxideBF₃
Boron trifluorideCCl₄
Carbon tetrachlorideSO₃
Sulfur trioxideSiCl₄
Silicon tetrachlorideP₂S₅
Diphosphorus pentasulfideBCl₃
Boron trichloridePBr₃
Phosphorus tribromideCBr₄
Carbon tetrabromideNF₃
Nitrogen trifluorideOF₂
Oxygen difluorideNCl₃
Nitrogen trichlorideH₂S
Hydrogen sulfidePH₃
PhosphineBeCl₂
Beryllium chlorideHCN
Hydrogen cyanideClF₃
Chlorine trifluorideXeF₂
Xenon difluorideTetrahedral
Trigonal pyramidal
Ammonia is a trigonal pyramidal molecule with a lone pair on nitrogen, which makes it a weak base and good ligand. It is central to industrial nitrogen chemistry.
Properties
Molar mass
17.031 g/mol
Boiling point
−33.4 °C
pKa (NH₄⁺)
9.25
Bond angle (H–N–H)
107.8°
Hybridization (N)
sp³
Uses
Fertilizer production · Household and industrial cleaners · Refrigeration systems · Precursor for many nitrogen compounds
Exam note
Systematic name
Ammonia
Compound class
It is a polar covalent molecule. The electron geometry is tetrahedral and the molecular shape is trigonal pyramidal.
Formula unit
Nitrogen has one lone pair. That pair makes ammonia a Lewis base.
Aqueous solution
It behaves as a weak base in water. The pKa of the ammonium ion is 9.25.
Watch the formula
With school atomic masses the molar mass is 17 g/mol: 14 (N) + 3×1 (H). The bond angle is not 109.5 degrees. The lone pair pushes the bonds, so the angle is about 107 degrees.
Sample reaction
N₂ + 3H₂ ⇌ 2NH₃
In the Haber process, nitrogen and hydrogen form ammonia with a catalyst and high pressure.
Molar mass calculation
Masses given in the question come first. When none are given, school values put the total at 17 g/mol.
+
= 17 g/mol
NH₃
The same count with periodic-table atomic masses gives 17.031 g/mol.
| Element | Atom count | Contribution (g/mol) | Mass % |
|---|---|---|---|
| Hydrogen (H) | 3 | 3.024 | 17.8 |
| Nitrogen (N) | 1 | 14.007 | 82.2 |
| Total | 17.031 | 100 |
Common questions
What is ammonia?
Ammonia is a trigonal pyramidal molecule with a lone pair on nitrogen, which makes it a weak base and good ligand. It is central to industrial nitrogen chemistry.
What is the formula of ammonia?
Ammonia is written NH₃. The systematic name is Ammonia. Nitrogen has one lone pair. That pair makes ammonia a Lewis base.
What is the molar mass of ammonia?
Ammonia has a molar mass of 17.031 g/mol from the atomic masses on the periodic table. With school atomic masses the total is 17 g/mol, counting 3 hydrogen and 1 nitrogen.
How does ammonia behave in water?
It behaves as a weak base in water. The pKa of the ammonium ion is 9.25.
What is a sample reaction for ammonia?
In the Haber process, nitrogen and hydrogen form ammonia with a catalyst and high pressure. N₂ + 3H₂ ⇌ 2NH₃
What is ammonia used for?
Ammonia is used for fertilizer production, household and industrial cleaners, refrigeration systems and precursor for many nitrogen compounds.
What should you watch for with ammonia on an exam?
With school atomic masses the molar mass is 17 g/mol: 14 (N) + 3×1 (H). The bond angle is not 109.5 degrees. The lone pair pushes the bonds, so the angle is about 107 degrees.