Enter the element symbol and the number of atoms for each element in your compound. You can use up to 4 elements.
Calculated Molar Mass:
Enter values and click 'Calculate'.
var atomicMasses = {
'H': 1.008, 'He': 4.0026, 'Li': 6.94, 'Be': 9.0122, 'B': 10.81,
'C': 12.011, 'N': 14.007, 'O': 15.999, 'F': 18.998, 'Ne': 20.180,
'Na': 22.990, 'Mg': 24.305, 'Al': 26.982, 'Si': 28.085, 'P': 30.974,
'S': 32.06, 'Cl': 35.45, 'K': 39.098, 'Ar': 39.948, 'Ca': 40.078,
'Sc': 44.956, 'Ti': 47.867, 'V': 50.942, 'Cr': 51.996, 'Mn': 54.938,
'Fe': 55.845, 'Co': 58.933, 'Ni': 58.693, 'Cu': 63.546, 'Zn': 65.38,
'Ga': 69.723, 'Ge': 72.63, 'As': 74.922, 'Se': 78.971, 'Br': 79.904,
'Kr': 83.798, 'Rb': 85.468, 'Sr': 87.62, 'Y': 88.906, 'Zr': 91.224,
'Nb': 92.906, 'Mo': 95.95, 'Tc': 98, 'Ru': 101.07, 'Rh': 102.906,
'Pd': 106.42, 'Ag': 107.868, 'Cd': 112.414, 'In': 114.818, 'Sn': 118.710,
'Sb': 121.760, 'I': 126.904, 'Te': 127.60, 'Xe': 131.293, 'Cs': 132.905,
'Ba': 137.327, 'La': 138.905, 'Ce': 140.116, 'Pr': 140.907, 'Nd': 144.242,
'Pm': 145, 'Sm': 150.36, 'Eu': 151.964, 'Gd': 157.25, 'Tb': 158.925,
'Dy': 162.500, 'Ho': 164.930, 'Er': 167.259, 'Tm': 168.934, 'Yb': 173.045,
'Lu': 174.967, 'Hf': 178.49, 'Ta': 180.948, 'W': 183.84, 'Re': 186.207,
'Os': 190.23, 'Ir': 192.217, 'Pt': 195.084, 'Au': 196.967, 'Hg': 200.59,
'Tl': 204.383, 'Pb': 207.2, 'Bi': 208.980, 'Po': 209, 'At': 210,
'Rn': 222, 'Fr': 223, 'Ra': 226, 'Ac': 227, 'Pa': 231.036,
'Th': 232.038, 'Np': 237, 'U': 238.029, 'Am': 243, 'Pu': 244,
'Cm': 247, 'Bk': 247, 'Cf': 251, 'Es': 252, 'Fm': 257,
'Md': 258, 'No': 259, 'Rf': 261, 'Lr': 262, 'Db': 262,
'Bh': 264, 'Sg': 266, 'Mt': 268, 'Rg': 272, 'Hs': 277
};
function calculateMolarMass() {
var totalMolarMass = 0;
var elementsProcessed = 0;
var errorMessages = [];
for (var i = 1; i <= 4; i++) {
var symbolId = "element" + i + "Symbol";
var countId = "element" + i + "Count";
var elementSymbol = document.getElementById(symbolId).value.trim().toUpperCase();
var elementCount = parseFloat(document.getElementById(countId).value);
if (elementSymbol === "" && (isNaN(elementCount) || elementCount === 0 || document.getElementById(countId).value.trim() === "")) {
// Both symbol and count are empty/zero/blank, skip this row
continue;
}
if (elementSymbol === "") {
errorMessages.push("Element " + i + ": Symbol cannot be empty if count is provided.");
continue;
}
if (isNaN(elementCount) || elementCount 0) {
resultDiv.innerHTML = "" + errorMessages.join("") + "";
} else if (elementsProcessed === 0) {
resultDiv.innerHTML = "Please enter at least one element and its count to calculate molar mass.";
} else {
resultDiv.innerHTML = "The molar mass is: " + totalMolarMass.toFixed(3) + " g/mol";
}
}
Understanding Molar Mass: A Fundamental Concept in Chemistry
Molar mass is a crucial concept in chemistry, representing the mass of one mole of a substance. A mole is a unit of measurement used in chemistry to express amounts of a chemical substance, defined as exactly 6.02214076 × 1023 particles (atoms, molecules, ions, etc.), a number known as Avogadro's number. The molar mass of a compound is typically expressed in grams per mole (g/mol).
Why is Molar Mass Important?
Molar mass serves as a bridge between the microscopic world of atoms and molecules and the macroscopic world of measurable quantities. It allows chemists to:
Convert between mass and moles: Essential for stoichiometric calculations in chemical reactions.
Determine empirical and molecular formulas: By comparing the mass of a sample to its molar mass.
Prepare solutions of specific concentrations: Knowing the molar mass helps in accurately weighing out solutes.
Understand the properties of substances: Molar mass can influence physical properties like boiling point, melting point, and density.
How to Calculate Molar Mass
Calculating the molar mass of a compound involves a straightforward process:
Identify the Chemical Formula: First, you need the correct chemical formula of the compound. This formula tells you which elements are present and how many atoms of each element are in one molecule or formula unit of the compound. For example, water is H2O, meaning it has two hydrogen atoms and one oxygen atom. Glucose is C6H12O6, indicating six carbon, twelve hydrogen, and six oxygen atoms.
Find the Atomic Mass of Each Element: Refer to a periodic table to find the average atomic mass for each element present in the compound. Atomic masses are usually listed below the element symbol and are typically given in atomic mass units (amu). For molar mass calculations, we use these values directly, but the units become grams per mole (g/mol). For instance, the atomic mass of Hydrogen (H) is approximately 1.008 g/mol, Carbon (C) is 12.011 g/mol, and Oxygen (O) is 15.999 g/mol.
Multiply Atomic Mass by the Number of Atoms: For each element in the compound, multiply its atomic mass by the number of times it appears in the chemical formula.
Sum the Products: Add up the results from step 3 for all the elements in the compound. The total sum will be the molar mass of the compound.
Example Calculation: Water (H2O)
Let's calculate the molar mass of water (H2O):
Hydrogen (H): Atomic mass = 1.008 g/mol. There are 2 hydrogen atoms.
Contribution from H = 2 × 1.008 g/mol = 2.016 g/mol
Oxygen (O): Atomic mass = 15.999 g/mol. There is 1 oxygen atom.
Contribution from O = 1 × 15.999 g/mol = 15.999 g/mol
Total Molar Mass of H2O = 2.016 g/mol + 15.999 g/mol = 18.015 g/mol
Example Calculation: Glucose (C6H12O6)
Let's calculate the molar mass of glucose (C6H12O6):
Carbon (C): Atomic mass = 12.011 g/mol. There are 6 carbon atoms.
Contribution from C = 6 × 12.011 g/mol = 72.066 g/mol
Hydrogen (H): Atomic mass = 1.008 g/mol. There are 12 hydrogen atoms.
Contribution from H = 12 × 1.008 g/mol = 12.096 g/mol
Oxygen (O): Atomic mass = 15.999 g/mol. There are 6 oxygen atoms.
Contribution from O = 6 × 15.999 g/mol = 95.994 g/mol
Total Molar Mass of C6H12O6 = 72.066 g/mol + 12.096 g/mol + 95.994 g/mol = 180.156 g/mol
Use the calculator above to quickly determine the molar mass for various compounds by entering the element symbols and their respective atom counts.