Enter the chemical formula for your compound to calculate its molecular weight in grams per mole (g/mol).
Enter the chemical formula, including element symbols and their subscripts (numbers).
Please enter a valid chemical formula.
Results
—
Total Atoms: — |
Unique Elements: — |
Sum of Atomic Masses: —
Molecular Weight (MW) = Σ (Atomic Mass of Element × Number of Atoms of Element in Formula)
Elemental Composition by Mass
Visual representation of the mass contribution of each element to the total molecular weight.
Atomic Mass Table
Standard atomic masses used in the calculation.
Element Symbol
Atomic Mass (g/mol)
Count in Formula
Mass Contribution (g/mol)
Enter a formula and calculate to see details here.
What is Molecular Weight?
Molecular weight, often used interchangeably with molar mass, is a fundamental property of a chemical compound. It represents the sum of the atomic masses of all atoms present in a single molecule of that compound. This value is crucial in various scientific disciplines, particularly in chemistry and biochemistry, for quantitative analysis, stoichiometry, and understanding chemical reactions.
Who Should Use It?
Anyone working with chemical compounds will find molecular weight calculations essential. This includes:
Students: Learning the basics of chemistry and stoichiometry.
Researchers: In academic and industrial labs for experimental design and data interpretation.
Chemists and Scientists: For precise calculations in synthesis, analysis, and formulation.
Pharmacists: Determining dosages and understanding drug compositions.
Material Scientists: Characterizing polymers and other materials.
Common Misconceptions
A common confusion arises between molecular weight and atomic weight. Atomic weight refers to the mass of a single atom of an element, while molecular weight applies to a compound composed of multiple atoms. Another misconception is that molecular weight is a direct measure of a substance's physical weight; it's a mass-based property measured in molar units (g/mol).
Molecular Weight Formula and Mathematical Explanation
The calculation for molecular weight is straightforward but requires accurate atomic masses and correct interpretation of the chemical formula. The core principle is to sum up the contributions of each atom within the molecule.
The Formula
The general formula to calculate the molecular weight (MW) of a compound is:
MW = Σ (Atomic Mass of Element × Number of Atoms of Element in Formula)
Step-by-Step Derivation
Identify the Chemical Formula: Precisely determine the chemical formula of the compound (e.g., H2O, C6H12O6).
List Elements and Counts: Break down the formula to identify each unique element present and the number of atoms of each element (the subscript number, or 1 if no subscript is shown).
Find Atomic Masses: Look up the standard atomic mass for each element from the periodic table. These are typically given in atomic mass units (amu), but for molecular weight calculations, they are expressed in grams per mole (g/mol).
Calculate Individual Mass Contributions: For each element, multiply its atomic mass by the number of atoms of that element in the formula.
Sum the Contributions: Add up the mass contributions calculated in the previous step for all elements in the compound. This sum is the molecular weight of the compound.
Variables Explanation
Understanding the variables involved is key to accurate calculation:
Variable
Meaning
Unit
Typical Range
Atomic Mass
The weighted average mass of atoms of an element, accounting for isotopes.
g/mol (grams per mole)
~0.5 (Hydrogen) to ~238 (Uranium) for stable elements
Number of Atoms
The count of a specific element's atoms within one molecule of the compound.
Unitless
1 or greater
Molecular Weight (MW)
The sum of the atomic masses of all atoms in a molecule.
g/mol
Varies widely depending on compound complexity
For example, in water (H2O):
Hydrogen (H): Atomic Mass ≈ 1.008 g/mol, Number of Atoms = 2
Oxygen (O): Atomic Mass ≈ 15.999 g/mol, Number of Atoms = 1
Interpretation: One mole of glucose molecules has a mass of approximately 180.156 grams. This value is used in calculating concentrations for biological experiments.
Example 2: Sodium Chloride (NaCl)
Sodium chloride, or common table salt, is an ionic compound. While technically it forms a crystal lattice rather than discrete molecules, the term "formula weight" is used, calculated similarly to molecular weight.
Inputs: Chemical Formula: NaCl
Atomic Masses:
Sodium (Na): 22.990 g/mol
Chlorine (Cl): 35.453 g/mol
Calculation:
Sodium: 22.990 g/mol × 1 = 22.990 g/mol
Chlorine: 35.453 g/mol × 1 = 35.453 g/mol
Output: Formula Weight = 22.990 + 35.453 = 58.443 g/mol
Interpretation: One mole of NaCl formula units has a mass of approximately 58.443 grams. This is vital for preparing saline solutions of specific molarities.
How to Use This Molecular Weight Calculator
Our calculator is designed for ease of use, providing quick and accurate molecular weight calculations. Follow these simple steps:
Step-by-Step Instructions
Enter the Chemical Formula: In the "Chemical Formula" input field, type the formula of the compound you wish to analyze. Ensure you use standard element symbols (e.g., H for Hydrogen, O for Oxygen, C for Carbon) and include the correct subscript numbers for each element. For example, use 'H2O' for water, 'C6H12O6' for glucose, and 'CO2' for carbon dioxide.
Click 'Calculate': Press the "Calculate" button. The calculator will parse your formula, look up the necessary atomic masses, and compute the molecular weight.
View Results: The calculated molecular weight will appear prominently in the "Results" section, displayed in g/mol. You will also see key intermediate values like the total number of atoms, the count of unique elements, and the sum of atomic masses.
Examine the Table: The "Atomic Mass Table" below will break down the calculation element by element, showing the atomic mass, its count in the formula, and its contribution to the total molecular weight.
Analyze the Chart: The "Elemental Composition by Mass" chart provides a visual representation of how much each element contributes to the overall molecular weight.
Reset or Copy: Use the "Reset" button to clear the fields and start a new calculation. Use the "Copy Results" button to copy all calculated values and key assumptions for use elsewhere.
How to Read Results
Main Result (g/mol): This is your primary molecular weight value. It tells you the mass of one mole of the substance.
Total Atoms: The total count of all atoms in one molecule/formula unit.
Unique Elements: The number of different elements present in the compound.
Sum of Atomic Masses: This is the direct result of summing up the atomic masses before considering the counts, essentially an intermediate step.
Atomic Mass Table: This table helps verify the calculation and understand the relative contribution of each element.
Chart: Visually confirms which elements contribute most to the molecular weight.
Decision-Making Guidance
Understanding molecular weight helps in making informed decisions:
Concentration Calculations: Knowing the MW allows you to accurately prepare solutions of specific molarities (moles per liter).
Stoichiometry: Essential for predicting reactant and product amounts in chemical reactions.
Purity Analysis: Comparing theoretical molecular weight to experimental data can help assess sample purity.
Reaction Feasibility: Lighter molecules might react differently or require different conditions than heavier ones.
Key Factors That Affect Molecular Weight Results
While the calculation itself is based on precise atomic masses, several factors can influence how molecular weight is applied or interpreted:
Accuracy of Atomic Masses: The values obtained from the periodic table are averages. For highly precise work, considering isotopic distribution might be necessary, though standard calculations use these average values.
Correct Chemical Formula: An incorrect or incomplete formula is the most common source of error. Including parentheses for polyatomic ions (e.g., (SO4)2) requires careful parsing.
Hydration: Compounds can incorporate water molecules into their crystal structure (hydrates, e.g., CuSO₄·5H₂O). The water molecules add significantly to the overall molecular weight.
Isotopic Variations: While standard atomic masses are used, naturally occurring samples may have slightly different isotopic ratios, leading to minor variations in actual molecular mass.
Charge on Ions: For ionic compounds, we calculate formula weight. The charge itself doesn't alter the mass of the constituent ions, but it dictates the compound's structure and reactivity.
Polymerization: For polymers, molecular weight can vary significantly depending on chain length. Average molecular weights (Mn, Mw) are often used instead of a single value.
Frequently Asked Questions (FAQ)
What is the difference between molecular weight and molar mass?
Technically, molecular weight is the mass of a single molecule in atomic mass units (amu), while molar mass is the mass of one mole of a substance in grams per mole (g/mol). However, in practice, these terms are often used interchangeably, and the numerical value is the same.
Can I use this calculator for ionic compounds?
Yes, although for ionic compounds, the term "formula weight" is more accurate than "molecular weight" because they form crystal lattices rather than discrete molecules. The calculation method is the same: sum the atomic masses of the atoms in the formula unit.
What if the chemical formula has parentheses, like Ca(OH)2?
The calculator should handle simple parentheses. For Ca(OH)2, the '2' outside the parenthesis multiplies the atoms inside. So, you have 1 Calcium (Ca), 2 Oxygen (O), and 2 Hydrogen (H) atoms.
How accurate are the atomic masses used?
The calculator uses standard, average atomic masses found on most periodic tables. These are highly accurate for general chemistry calculations but may differ slightly from the mass of specific isotopes or isotopically enriched samples.
What units is the molecular weight calculated in?
The molecular weight is calculated and displayed in grams per mole (g/mol), which is the standard unit for molar mass.
Does the calculator handle complex formulas with multiple sets of parentheses?
This calculator is designed for common chemical formulas. Very complex formulas with nested parentheses or unusual notation might require manual parsing or specialized software.
What does "Total Atoms" in the results mean?
It's the sum of all the subscript numbers in the chemical formula, representing the total number of individual atoms making up one molecule or formula unit of the compound.
Why is molecular weight important in chemistry?
It's essential for quantitative chemistry. It allows chemists to relate mass to moles, enabling calculations for reaction yields, solution concentrations, and understanding the physical properties of substances.
// Mock atomic mass data – in a real scenario, this would be more comprehensive
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, "Ar": 39.948,
"K": 39.098, "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": 72.630, "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": 98.0, "Ru": 101.07, "Rh": 102.91, "Pd": 106.42, "Ag": 107.87, "Cd": 112.41, "In": 114.82, "Sn": 118.71, "Sb": 121.76, "Te": 127.60, "I": 126.90, "Xe": 131.29,
"Cs": 132.91, "Ba": 137.33, "La": 138.91, "Ce": 140.12, "Pr": 140.91, "Nd": 144.24, "Pm": 145.0, "Sm": 150.36, "Eu": 151.96, "Gd": 157.25, "Tb": 158.93, "Dy": 162.50, "Ho": 164.93, "Er": 167.26, "Tm": 168.93, "Yb": 173.05, "Lu": 174.97,
"Hf": 178.49, "Ta": 180.95, "W": 183.84, "Re": 186.21, "Os": 190.23, "Ir": 192.22, "Pt": 195.08, "Au": 196.97, "Hg": 200.59, "Tl": 204.38, "Pb": 207.2, "Bi": 208.98, "Po": 209.0, "At": 210.0, "Rn": 222.0
};
var chartInstance = null;
function isValidElement(elementSymbol) {
return atomicMasses.hasOwnProperty(elementSymbol);
}
function parseChemicalFormula(formula) {
var elements = {};
var totalAtoms = 0;
var regex = /([A-Z][a-z]*)(\d*)|(\()([A-Z][a-z]*)(\d*)(\))(\d*)/g;
var match;
var elementCounts = {};
// Simple regex for parsing basic formulas, handling simple parentheses like (OH)2
// This is a simplified parser for demonstration. Real-world parsers are more complex.
regex = /([A-Z][a-z]*)(\d*)|(\()([A-Z][a-z]*)(\d*)(\))(\d*)/g;
var tempFormula = formula;
// Process simple parenthesized groups first
while (tempFormula.match(/\([^()]+\)\d*/)) {
tempFormula = tempFormula.replace(/\(([^()]+)\)(\d*)/g, function(match, inner, multiplier) {
var innerElements = {};
var innerRegex = /([A-Z][a-z]*)(\d*)/g;
var innerMatch;
while ((innerMatch = innerRegex.exec(inner)) !== null) {
var element = innerMatch[1];
var count = innerMatch[2] ? parseInt(innerMatch[2], 10) : 1;
innerElements[element] = (innerElements[element] || 0) + count;
}
var effectiveMultiplier = multiplier ? parseInt(multiplier, 10) : 1;
var result = "";
for (var el in innerElements) {
result += el + (innerElements[el] * effectiveMultiplier);
}
return result;
});
}
// Now parse the simplified formula
regex = /([A-Z][a-z]*)(\d*)/g;
while ((match = regex.exec(tempFormula)) !== null) {
var element = match[1];
var count = match[2] ? parseInt(match[2], 10) : 1;
if (!isValidElement(element)) {
console.error("Unknown element:", element);
return null; // Indicate invalid formula
}
elements[element] = (elements[element] || 0) + count;
totalAtoms += count;
}
return { elements: elements, totalAtoms: totalAtoms };
}
function validateInput() {
var formulaInput = document.getElementById("chemicalFormula");
var formulaError = document.getElementById("formulaError");
var formula = formulaInput.value.trim();
formulaError.style.display = "none"; // Hide error initially
if (formula === "") {
formulaError.textContent = "Chemical formula cannot be empty.";
formulaError.style.display = "block";
return false;
}
// Basic check for invalid characters (allowing letters, numbers, parentheses)
if (!/^[A-Za-z0-9()]+$/.test(formula)) {
formulaError.textContent = "Formula contains invalid characters.";
formulaError.style.display = "block";
return false;
}
// Attempt to parse to check validity of structure and elements
var parsed = parseChemicalFormula(formula);
if (!parsed) {
formulaError.textContent = "Invalid chemical formula structure or unknown element.";
formulaError.style.display = "block";
return false;
}
return true;
}
function calculateMolecularWeight() {
var formulaInput = document.getElementById("chemicalFormula");
var formula = formulaInput.value.trim();
var resultsContainer = document.getElementById("resultsContainer");
var mainResult = document.getElementById("mainResult");
var totalAtomsSpan = document.getElementById("totalAtoms");
var uniqueElementsSpan = document.getElementById("uniqueElements");
var sumAtomicMassesSpan = document.getElementById("sumAtomicMasses");
var tableBody = document.getElementById("atomicMassTableBody");
tableBody.innerHTML = ""; // Clear previous table data
if (!validateInput()) {
resultsContainer.style.display = "none";
return;
}
var parsedFormula = parseChemicalFormula(formula);
var elements = parsedFormula.elements;
var totalAtoms = parsedFormula.totalAtoms;
var molecularWeight = 0;
var elementData = [];
for (var elementSymbol in elements) {
if (elements.hasOwnProperty(elementSymbol)) {
var atomicMass = atomicMasses[elementSymbol];
var count = elements[elementSymbol];
var massContribution = atomicMass * count;
molecularWeight += massContribution;
elementData.push({
symbol: elementSymbol,
atomicMass: atomicMass.toFixed(3),
count: count,
contribution: massContribution.toFixed(3)
});
}
}
// Sort element data for consistent table display
elementData.sort(function(a, b) {
return a.symbol.localeCompare(b.symbol);
});
// Populate table
elementData.forEach(function(data) {
var row = tableBody.insertRow();
row.insertCell(0).textContent = data.symbol;
row.insertCell(1).textContent = data.atomicMass;
row.insertCell(2).textContent = data.count;
row.insertCell(3).textContent = data.contribution;
});
// Update results display
mainResult.textContent = molecularWeight.toFixed(3) + " g/mol";
totalAtomsSpan.textContent = totalAtoms;
uniqueElementsSpan.textContent = Object.keys(elements).length;
sumAtomicMassesSpan.textContent = molecularWeight.toFixed(3) + " g/mol"; // This is the same as MW in this context
resultsContainer.style.display = "block";
updateChart(elementData);
}
function updateChart(elementData) {
var canvas = document.getElementById('molecularWeightChart');
var ctx = canvas.getContext('2d');
// Clear previous chart
if (chartInstance) {
chartInstance.destroy();
}
var labels = [];
var dataValues = [];
var colors = [];
// Basic color palette – extend this for more elements if needed
var colorPalette = [
'#004a99', '#28a745', '#dc3545', '#ffc107', '#17a2b8', '#6f42c1',
'#fd7e14', '#6c757d', '#20c997', '#343a40', '#e83e8c', '#6610f2'
];
var colorIndex = 0;
elementData.forEach(function(item) {
labels.push(item.symbol);
dataValues.push(parseFloat(item.contribution));
colors.push(colorPalette[colorIndex % colorPalette.length]);
colorIndex++;
});
chartInstance = new Chart(ctx, {
type: 'pie',
data: {
labels: labels,
datasets: [{
label: 'Mass Contribution (g/mol)',
data: dataValues,
backgroundColor: colors,
borderColor: '#ffffff',
borderWidth: 1
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
legend: {
position: 'top',
},
title: {
display: true,
text: 'Elemental Mass Contribution'
},
plugins: {
tooltip: {
callbacks: {
label: function(context) {
var label = context.label || ";
if (label) {
label += ': ';
}
if (context.parsed !== null) {
label += context.parsed.toFixed(3) + ' g/mol';
}
return label;
}
}
}
}
}
});
}
function resetCalculator() {
document.getElementById("chemicalFormula").value = "";
document.getElementById("resultsContainer").style.display = "none";
document.getElementById("atomicMassTableBody").innerHTML = '
Enter a formula and calculate to see details here.
';
if (chartInstance) {
chartInstance.destroy();
chartInstance = null;
}
// Clear error messages
document.getElementById("formulaError").style.display = "none";
}
function copyResults() {
var mainResult = document.getElementById("mainResult").textContent;
var totalAtoms = document.getElementById("totalAtoms").textContent;
var uniqueElements = document.getElementById("uniqueElements").textContent;
var sumAtomicMasses = document.getElementById("sumAtomicMasses").textContent;
var formula = document.getElementById("chemicalFormula").value.trim();
if (mainResult === "–") {
alert("No results to copy yet. Please calculate first.");
return;
}
var tableRows = document.getElementById("atomicMassTableBody").rows;
var tableContent = "Element Symbol\tAtomic Mass (g/mol)\tCount in Formula\tMass Contribution (g/mol)\n";
for (var i = 0; i < tableRows.length; i++) {
var cells = tableRows[i].cells;
if(cells.length === 4) { // Ensure it's a data row, not the placeholder
tableContent += cells[0].textContent + "\t" +
cells[1].textContent + "\t" +
cells[2].textContent + "\t" +
cells[3].textContent + "\n";
}
}
var assumptions = "Assumptions:\n" +
"Formula Used: " + formula + "\n" +
"Atomic Masses based on standard periodic table values.";
var textToCopy = "Molecular Weight Calculation Results:\n\n" +
"Molecular Weight: " + mainResult + "\n" +
"Total Atoms: " + totalAtoms + "\n" +
"Unique Elements: " + uniqueElements + "\n" +
"Sum of Atomic Masses: " + sumAtomicMasses + "\n\n" +
"Elemental Breakdown:\n" + tableContent + "\n" +
assumptions;
// Use a temporary textarea to copy text to clipboard
var textArea = document.createElement("textarea");
textArea.value = textToCopy;
textArea.style.position = "fixed";
textArea.style.left = "-9999px";
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'Results copied to clipboard!' : 'Failed to copy results.';
alert(msg);
} catch (err) {
alert('Failed to copy results. Your browser may not support this feature.');
}
document.body.removeChild(textArea);
}
function toggleFaq(element) {
var paragraph = element.nextElementSibling;
if (paragraph.style.display === "block") {
paragraph.style.display = "none";
} else {
paragraph.style.display = "block";
}
}
// Add event listener for Enter key on formula input
document.getElementById("chemicalFormula").addEventListener("keypress", function(event) {
if (event.key === "Enter") {
event.preventDefault(); // Prevent default form submission if it were in a form
calculateMolecularWeight();
}
});
// Initial chart setup placeholder
// The actual chart will be drawn when calculateMolecularWeight is called.
window.onload = function() {
var canvas = document.getElementById('molecularWeightChart');
var ctx = canvas.getContext('2d');
// You might want to draw a placeholder or instructions on the canvas initially
ctx.fillStyle = "#e0e0e0";
ctx.fillRect(0, 0, canvas.width, canvas.height);
ctx.font = "16px Arial";
ctx.fillStyle = "#555";
ctx.textAlign = "center";
ctx.fillText("Enter a chemical formula and calculate to see the chart.", canvas.width/2, canvas.height/2);
// Dynamically load Chart.js if not already present, otherwise assume it's globally available
// For this standalone HTML, we'll include it via CDN in a real scenario or embed it.
// Since the prompt says NO external libraries, we need to ensure Chart.js is embedded or not used.
// The prompt says "Pure SVG or Native Canvas". Chart.js is an external library.
// I will adapt to use native canvas API for drawing, removing Chart.js dependency.
// Re-implementing chart drawing using native canvas API
updateChartNativeCanvas([]); // Call with empty data initially to show placeholder
};
// Native Canvas Drawing Functions (Replacing Chart.js)
function updateChartNativeCanvas(elementData) {
var canvas = document.getElementById('molecularWeightChart');
var ctx = canvas.getContext('2d');
var width = canvas.width;
var height = canvas.height;
ctx.clearRect(0, 0, width, height); // Clear canvas
if (elementData.length === 0) {
ctx.font = "16px Arial";
ctx.fillStyle = "#555";
ctx.textAlign = "center";
ctx.fillText("Enter a chemical formula and calculate to see the chart.", width / 2, height / 2);
return;
}
// Calculate total mass for percentage calculation
var totalMass = elementData.reduce(function(sum, item) {
return sum + parseFloat(item.contribution);
}, 0);
// Drawing a Pie Chart manually
var startAngle = 0;
var centerX = width / 2;
var centerY = height / 2;
var radius = Math.min(width, height) / 2 * 0.8; // Make radius slightly smaller than half the canvas size
// Basic color palette
var colorPalette = [
'#004a99', '#28a745', '#dc3545', '#ffc107', '#17a2b8', '#6f42c1',
'#fd7e14', '#6c757d', '#20c997', '#343a40', '#e83e8c', '#6610f2'
];
var colorIndex = 0;
// Draw slices
elementData.forEach(function(item) {
var percentage = parseFloat(item.contribution) / totalMass;
var sliceAngle = percentage * 2 * Math.PI;
var color = colorPalette[colorIndex % colorPalette.length];
ctx.fillStyle = color;
ctx.beginPath();
ctx.moveTo(centerX, centerY);
ctx.arc(centerX, centerY, radius, startAngle, startAngle + sliceAngle);
ctx.closePath();
ctx.fill();
// Draw labels – approximate positioning
var midAngle = startAngle + sliceAngle / 2;
var labelX = centerX + (radius * 0.7) * Math.cos(midAngle);
var labelY = centerY + (radius * 0.7) * Math.sin(midAngle);
ctx.fillStyle = '#000'; // Text color
ctx.font = '12px Arial';
ctx.textAlign = 'center';
ctx.fillText(item.symbol + ` (${(percentage * 100).toFixed(1)}%)`, labelX, labelY);
startAngle += sliceAngle;
colorIndex++;
});
// Draw a simple legend
var legendX = width – 150; // Position legend on the right
var legendY = 20;
var legendItemHeight = 20;
ctx.font = '12px Arial';
ctx.textAlign = 'left';
elementData.forEach(function(item, index) {
var color = colorPalette[index % colorPalette.length];
ctx.fillStyle = color;
ctx.fillRect(legendX, legendY + index * legendItemHeight, 15, 15); // Color square
ctx.fillStyle = '#333'; // Text color
ctx.fillText(item.symbol + ": " + item.contribution + " g/mol", legendX + 20, legendY + index * legendItemHeight + 12);
});
// Add a title
ctx.font = '18px Arial';
ctx.fillStyle = '#004a99';
ctx.textAlign = 'center';
ctx.fillText("Elemental Mass Contribution", width / 2, 15);
}
// Override the previous chartInstance variable if it existed
var chartInstance = { destroy: function() { /* No-op for native canvas */ } };
// Need to call the native update function instead of the Chart.js one
function calculateMolecularWeight() { // Redefining to use native canvas update
var formulaInput = document.getElementById("chemicalFormula");
var formula = formulaInput.value.trim();
var resultsContainer = document.getElementById("resultsContainer");
var mainResult = document.getElementById("mainResult");
var totalAtomsSpan = document.getElementById("totalAtoms");
var uniqueElementsSpan = document.getElementById("uniqueElements");
var sumAtomicMassesSpan = document.getElementById("sumAtomicMasses");
var tableBody = document.getElementById("atomicMassTableBody");
tableBody.innerHTML = ""; // Clear previous table data
if (!validateInput()) {
resultsContainer.style.display = "none";
return;
}
var parsedFormula = parseChemicalFormula(formula);
var elements = parsedFormula.elements;
var totalAtoms = parsedFormula.totalAtoms;
var molecularWeight = 0;
var elementData = [];
for (var elementSymbol in elements) {
if (elements.hasOwnProperty(elementSymbol)) {
var atomicMass = atomicMasses[elementSymbol];
var count = elements[elementSymbol];
var massContribution = atomicMass * count;
molecularWeight += massContribution;
elementData.push({
symbol: elementSymbol,
atomicMass: atomicMass.toFixed(3),
count: count,
contribution: massContribution.toFixed(3)
});
}
}
// Sort element data for consistent table display
elementData.sort(function(a, b) {
return a.symbol.localeCompare(b.symbol);
});
// Populate table
elementData.forEach(function(data) {
var row = tableBody.insertRow();
row.insertCell(0).textContent = data.symbol;
row.insertCell(1).textContent = data.atomicMass;
row.insertCell(2).textContent = data.count;
row.insertCell(3).textContent = data.contribution;
});
// Update results display
mainResult.textContent = molecularWeight.toFixed(3) + " g/mol";
totalAtomsSpan.textContent = totalAtoms;
uniqueElementsSpan.textContent = Object.keys(elements).length;
sumAtomicMassesSpan.textContent = molecularWeight.toFixed(3) + " g/mol"; // This is the same as MW in this context
resultsContainer.style.display = "block";
updateChartNativeCanvas(elementData); // Use the native canvas drawing function
}
// Need to ensure window.onload calls the native canvas update too
window.onload = function() {
updateChartNativeCanvas([]); // Call with empty data initially to show placeholder
};