Molecular Weight Calculator
The molecular weight of a chemical compound can be calculated using the Molecular Weight Calculator, which is a useful online tool. Enter the chemical compound as input and examine the molecular weight as output in a matter of seconds by clicking the blue colour calculate button.
Molecular Weight Calculator: This simple calculator makes calculating the molecular weight of a substance simple. This user-friendly tool provides accurate results in a short amount of time. In the following section, you'll learn how to compute a substance's molecular weight, the major difference between molar mass and molecular weight, and several solved examples.
Steps to Calculate the Molecular Weight
Have a look at the step by step procedure on how to find any chemical compound molecular weight easily.
- Let us take any chemical compound.
- Get the atomic weight of the each of the element included in the compound.
- Also, make a note of the number of atoms of each type.
- Multiply the number of atoms by the atomic weight of each element
- Add the products to get the final molecular weight.
Molar Mass Versus Molecular Weight
Molar mass and molecular weight are identical values, but they are not exactly the same
| Molar Mass | Molecular Weight |
|---|---|
| It is the mass of a mole of a substance | It is the mass of the single molecule of the substance |
| The SI unit is g/mol | Measured in amu or u |
| Defined as the mass of Avogadro number of atoms | Defined as the sum of the atomic masses of all atoms in a molecule of the substance |
| Molar mass of HCl is 17g/mol | Molecular weight of HCl is 36.5 u. |
Table of Atomic Weights and Elements
| Atomic Number | Element Name | Atomic Symbol | Atomic Weight (g/mol) |
|---|---|---|---|
| 1 | Hydrogen | H | 1.00794 |
| 2 | Helium | He | 4.002602 |
| 3 | Lithium | Li | 6.941 |
| 4 | Beryllium | Be | 9.012182 |
| 5 | Boron | B | 10.811 |
| 6 | Carbon | C | 12.0107 |
| 7 | Nitrogen | N | 14.0067 |
| 8 | Oxygen | O | 15.9994 |
| 9 | Fluorine | F | 18.9984032 |
| 10 | Neon | Ne | 20.1797 |
| 11 | Sodium | Na | 22.98976928 |
| 12 | Magnesium | Mg | 24.3050 |
| 13 | Aluminum | Al | 26.9815386 |
| 14 | Silicon | Si | 28.0855 |
| 15 | Phosphorus | P | 30.973762 |
| 16 | Sulfur | S | 32.065 |
| 17 | Chlorine | Cl | 35.453 |
| 18 | Argon | Ar | 39.948 |
| 19 | Potassium | K | 39.0983 |
| 20 | Calcium | Ca | 40.078 |
| 21 | Scandium | Sc | 44.955912 |
| 22 | Titanium | Ti | 47.867 |
| 23 | Vanadium | V | 50.9415 |
| 24 | Chromium | Cr | 51.9961 |
| 25 | Manganese | Mn | 54.938045 |
| 26 | Iron | Fe | 55.845 |
| 27 | Cobalt | Co | 58.933195 |
| 28 | Nickel | Ni | 58.6934 |
| 29 | Copper | Cu | 63.546 |
| 30 | Zinc | Zn | 65.409 |
| 31 | Gallium | Ga | 69.723 |
| 32 | Germanium | Ge | 72.64 |
| 33 | Arsenic | As | 74.92160 |
| 34 | Selenium | Se | 78.96 |
| 35 | Bromine | Br | 79.904 |
| 36 | Krypton | Kr | 83.798 |
| 37 | Rubidium | Rb | 85.4678 |
| 38 | Strontium | Sr | 87.62 |
| 39 | Yttrium | Y | 88.90585 |
| 40 | Zirconium | Zr | 91.224 |
| 41 | Niobium | Nb | 92.906 38 |
| 42 | Molybdenum | Mo | 95.94 |
| 43 | Technetium | Tc | 98.9063 |
| 44 | Ruthenium | Ru | 101.07 |
| 45 | Rhodium | Rh | 102.90550 |
| 46 | Palladium | Pd | 106.42 |
| 47 | Silver | Ag | 107.8682 |
| 48 | Cadmium | Cd | 112.411 |
| 49 | Indium | In | 114.818 |
| 50 | Tin | Sn | 118.710 |
| 51 | Antimony | Sb | 121.760 |
| 52 | Tellurium | Te | 127.60 |
| 53 | Iodine | I | 126.90447 |
| 54 | Xenon | Xe | 131.293 |
| 55 | Caesium | Cs | 132.9054519 |
| 56 | Barium | Ba | 137.327 |
| 57 | Lanthanum | La | 138.90547 |
| 58 | Cerium | Ce | 140.116 |
| 59 | Praseodymium | Pr | 140.90765 |
| 60 | Neodymium | Nd | 144.242 |
| 61 | Promethium | Pm | 146.9151 |
| 62 | Samarium | Sm | 150.36 |
| 63 | Europium | Eu | 151.964 |
| 64 | Gadolinium | Gd | 157.25 |
| 65 | Terbium | Tb | 158.92535 |
| 66 | Dysprosium | Dy | 162.500 |
| 67 | Holmium | Ho | 164.93032 |
| 68 | Erbium | Er | 167.259 |
| 69 | Thulium | Tm | 168.93421 |
| 70 | Ytterbium | Yb | 173.04 |
| 71 | Lutetium | Lu | 174.967 |
| 72 | Hafnium | Hf | 178.49 |
| 73 | Tantalum | Ta | 180.9479 |
| 74 | Tungsten | W | 183.84 |
| 75 | Rhenium | Re | 186.207 |
| 76 | Osmium | Os | 190.23 |
| 77 | Iridium | Ir | 192.217 |
| 78 | Platinum | Pt | 195.084 |
| 79 | Gold | Au | 196.966569 |
| 80 | Mercury | Hg | 200.59 |
| 81 | Thallium | Tl | 204.3833 |
| 82 | Lead | Pb | 207.2 |
| 83 | Bismuth | Bi | 208.98040 |
| 84 | Polonium | Po | 208.9824 |
| 85 | Astatine | At | 209.9871 |
| 86 | Radon | Rn | 222.0176 |
| 87 | Francium | Fr | 223.0197 |
| 88 | Radium | Ra | 226.0254 |
| 89 | Actinium | Ac | 227.0278 |
| 90 | Thorium | Th | 232.03806 |
| 91 | Protactinium | Pa | 231.03588 |
| 92 | Uranium | U | 238.02891 |
| 93 | Neptunium | Np | 237.0482 |
| 94 | Plutonium | Pu | 244.0642 |
| 95 | Americium | Am | 243.0614 |
| 96 | Curium | Cm | 247.0703 |
| 97 | Berkelium | Bk | 247.0703 |
| 98 | Californium | Cf | 251.0796 |
| 99 | Einsteinium | Es | 252.0829 |
| 100 | Fermium | Fm | 257.0951 |
| 101 | Mendelevium | Md | 258.0986 |
| 102 | Nobelium | No | 259.1009 |
| 103 | Lawrencium | Lr | 260.1053 |
| 104 | Rutherfordium | Rf | 261.1087 |
| 105 | Dubnium | Db | 262.1138 |
| 106 | Seaborgium | Sg | 263.1182 |
| 107 | Bohrium | Bh | 262.1229 |
| 108 | Hassium | Hs | 265 |
| 109 | Meitnerium | Mt | 266 |
| 110 | Darmstadtium | Ds | 269 |
| 111 | Roentgenium | Rg | 272 |
| 112 | Ununbium | Uub | 285 |
| 113 | Ununtrium | Uut | 284 |
| 114 | Ununquadium | Uuq | 289 |
| 115 | Ununpentium | Uup | 288 |
| 116 | Ununhexium | Uuh | 292 |
| 118 | Ununoctium | Uuo | 294 |
Example:
Question: Find the molecular weight of H2SO4?
Answer:
Given chemical compound is H2SO4
The number hydrogen atoms = 2
The number of Sulphur atoms = 1
The number of oxygen atoms = 4
Mass of hydrogen = 1 u
Mass of sulphur = 32.06 u
Mass of oxygen = 15.99 u
Molecular weight of H2SO4 = (2 x 1) + 32.06 + (4 x 15.99)
= 2 + 32.06 + 63.96 = 98.02
Therefore, H2SO4 MW is 98.02 u
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FAQ’s on Molecular Weight Calculator
1. How to use Molecular Weight Calculator?
You have to enter the chemical compound in the input field and press the calculate button to check the molecular weight of that compound easily.
2. What are the differences between molar mass and molecular weight?
The molar mass is defined as the mass of the mole of a substance and its unit is gram per mol. The molecular weight is the mass of a molecule and its unit is an atomic unit. Molar mass is calculated by dividing the mass of the substance by the amount of the substance. Molecular weight is 1/12th of the mass of the carbon-12 atom.
3. Find the molecular weight of NaCl?
Given chemical compound is NaCl
The atomic weight of Na = 22.98
The atomic weight of Cl = 35.45
The molecular weight of NaCl = 1 x 22.98 + 1 x 35.45 = 58.43 u.
4. What is the molecular weight definition?
The molecular weight is defined as the mass of a molecule of a substance. Its unit is an atomic unit and it is also called the relative molecular weight.