.empirical-formula-calculator-wrapper {
font-family: Arial, sans-serif;
line-height: 1.6;
color: #333;
max-width: 800px;
margin: 0 auto;
padding: 20px;
background: #fff;
border-radius: 8px;
box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}
.empirical-formula-calculator-wrapper h2,
.empirical-formula-calculator-wrapper h3 {
color: #2c3e50;
margin-top: 25px;
margin-bottom: 15px;
border-bottom: 1px solid #eee;
padding-bottom: 5px;
}
.empirical-formula-calculator-wrapper p {
margin-bottom: 10px;
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.empirical-formula-calculator-wrapper ul,
.empirical-formula-calculator-wrapper ol {
margin-left: 25px;
margin-bottom: 15px;
}
.empirical-formula-calculator-wrapper li {
margin-bottom: 5px;
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.calculator-container {
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border: 1px solid #ddd;
padding: 20px;
border-radius: 8px;
margin-top: 20px;
}
.input-group {
margin-bottom: 15px;
padding: 10px;
border: 1px solid #eee;
border-radius: 5px;
background-color: #fff;
display: flex;
flex-wrap: wrap;
align-items: center;
gap: 10px;
}
.input-group label {
font-weight: bold;
white-space: nowrap;
}
.input-group input[type="text"],
.input-group input[type="number"] {
padding: 8px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box;
flex-grow: 1;
min-width: 80px; /* Ensure inputs don't get too small */
}
.input-group label[for^="elementName"] {
flex-basis: 100px; /* Fixed width for element name label */
}
.input-group input[id^="elementName"] {
flex-basis: 80px; /* Fixed width for element name input */
flex-grow: 0;
}
.input-group label[for^="elementMass"],
.input-group label[for^="elementMolarMass"] {
flex-basis: 120px; /* Fixed width for mass/molar mass labels */
}
.input-group input[id^="elementMass"],
.input-group input[id^="elementMolarMass"] {
flex-basis: 120px; /* Fixed width for mass/molar mass inputs */
flex-grow: 0;
}
button {
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padding: 12px 20px;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 17px;
width: 100%;
box-sizing: border-box;
margin-top: 10px;
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button:hover {
background-color: #0056b3;
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margin-top: 20px;
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background-color: #d4edda;
border-radius: 5px;
color: #155724;
font-weight: bold;
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color: #155724;
margin-top: 10px;
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.calculator-result table {
width: 100%;
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margin-top: 10px;
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@media (max-width: 600px) {
.input-group {
flex-direction: column;
align-items: stretch;
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.input-group label,
.input-group input {
width: 100% !important;
flex-basis: auto !important;
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}
function calculateEmpiricalFormula() {
var elementsData = [];
var resultDiv = document.getElementById("empiricalFormulaResult");
resultDiv.innerHTML = ""; // Clear previous results
var numElements = 4; // Number of element input groups
for (var i = 1; i <= numElements; i++) {
var elementName = document.getElementById("elementName" + i).value.trim();
var elementMassStr = document.getElementById("elementMass" + i).value.trim();
var elementMolarMassStr = document.getElementById("elementMolarMass" + i).value.trim();
if (elementName === "" && elementMassStr === "" && elementMolarMassStr === "") {
continue; // Skip entirely empty rows
}
var elementMass = parseFloat(elementMassStr);
var elementMolarMass = parseFloat(elementMolarMassStr);
if (elementName === "") {
resultDiv.innerHTML = "Error: Element " + i + " name cannot be empty if other fields are filled.";
return;
}
if (isNaN(elementMass) || elementMass <= 0) {
resultDiv.innerHTML = "Error: Please enter a valid positive mass (or percentage) for " + elementName + ".";
return;
}
if (isNaN(elementMolarMass) || elementMolarMass <= 0) {
resultDiv.innerHTML = "Error: Please enter a valid positive molar mass for " + elementName + ".";
return;
}
elementsData.push({
name: elementName,
mass: elementMass,
molarMass: elementMolarMass,
moles: 0,
ratio: 0,
wholeRatio: 0
});
}
if (elementsData.length === 0) {
resultDiv.innerHTML = "Please enter data for at least one element.";
return;
}
// Step 1: Convert mass to moles
var smallestMoles = Infinity;
for (var j = 0; j < elementsData.length; j++) {
elementsData[j].moles = elementsData[j].mass / elementsData[j].molarMass;
if (elementsData[j].moles < smallestMoles) {
smallestMoles = elementsData[j].moles;
}
}
if (smallestMoles === 0) {
resultDiv.innerHTML = "Error: Cannot calculate with zero moles for all elements. Check your inputs.";
return;
}
// Step 2: Determine the smallest mole ratio
var hasNonWholeRatio = false;
var tempRatios = [];
for (var k = 0; k 0.01) { // Check if not close to a whole number
hasNonWholeRatio = true;
}
}
// Step 3: Convert to whole numbers if necessary
var multiplier = 1;
if (hasNonWholeRatio) {
// Try common multipliers (2, 3, 4, 5, 6, 7, 8, 9, 10)
var foundMultiplier = false;
for (var m = 2; m <= 10; m++) { // Iterate through potential multipliers
var allWhole = true;
for (var n = 0; n 0.01) {
allWhole = false;
break;
}
}
if (allWhole) {
multiplier = m;
foundMultiplier = true;
break;
}
}
if (!foundMultiplier) {
resultDiv.innerHTML += "Warning: Could not find a simple whole-number multiplier for ratios. Results might be rounded. Please double-check your input values for accuracy.";
}
}
var empiricalFormula = "";
var detailedResults = "";
detailedResults += "
";
if (empiricalFormula === "") {
resultDiv.innerHTML = "Could not determine an empirical formula. Please check your inputs.";
return;
}
resultDiv.innerHTML += "The Empirical Formula is: " + empiricalFormula + "";
resultDiv.innerHTML += detailedResults;
}
What is an Empirical Formula?
The empirical formula of a chemical compound is the simplest whole-number ratio of atoms present in a compound. It provides the lowest whole-number ratio of elements in a compound, but not necessarily the actual number of atoms in a molecule (which is given by the molecular formula).
For example, the molecular formula for glucose is C6H12O6. Its empirical formula, however, is CH2O, because the ratio of carbon to hydrogen to oxygen atoms (6:12:6) can be simplified to 1:2:1.
Why is the Empirical Formula Important?
- It's often the first step in determining the molecular formula of an unknown compound.
- It's crucial in analytical chemistry for characterizing new substances.
- It helps in understanding the basic composition of a compound.
How to Calculate the Empirical Formula
The calculation of an empirical formula typically involves these steps:
- Convert Mass or Percentage to Moles: If you're given percentages, assume a 100-gram sample so that the percentages directly translate to grams. Then, divide the mass of each element by its molar mass to find the number of moles.
- Determine the Smallest Mole Ratio: Divide the number of moles of each element by the smallest number of moles calculated in the previous step. This will give you a preliminary mole ratio.
- Convert to Whole Numbers: If the ratios from step 2 are not whole numbers, multiply all the ratios by the smallest integer that will convert all of them into whole numbers. Common multipliers are 2 (for ratios ending in .5), 3 (for ratios ending in .33 or .66), 4 (for ratios ending in .25 or .75), or 5 (for ratios ending in .2, .4, .6, .8).
- Write the Empirical Formula: Use the whole-number ratios as subscripts for each element in the formula.
Example Calculation:
A compound is found to contain 40.0% Carbon, 6.7% Hydrogen, and 53.3% Oxygen. Let's determine its empirical formula.
- Convert to Moles (assuming 100g sample):
- Carbon (C): 40.0 g / 12.011 g/mol = 3.330 mol
- Hydrogen (H): 6.7 g / 1.008 g/mol = 6.647 mol
- Oxygen (O): 53.3 g / 15.999 g/mol = 3.331 mol
- Determine Smallest Mole Ratio: The smallest number of moles is 3.330 mol (Carbon).
- C: 3.330 mol / 3.330 mol = 1.00
- H: 6.647 mol / 3.330 mol = 1.996 ≈ 2.00
- O: 3.331 mol / 3.330 mol = 1.000 ≈ 1.00
- Convert to Whole Numbers: All ratios are already whole numbers (or very close).
- Write the Empirical Formula: CH2O
Empirical Formula Calculator
Enter the element name, its mass (or percentage), and its molar mass. You can add up to 4 elements.
Calculation Details:
"; detailedResults += "| Element | Mass (g or %) | Molar Mass (g/mol) | Moles | Mole Ratio (divided by smallest) | Whole Number Ratio |
|---|---|---|---|---|---|
| " + elementsData[p].name + " | "; detailedResults += "" + elementsData[p].mass.toFixed(3) + " | "; detailedResults += "" + elementsData[p].molarMass.toFixed(3) + " | "; detailedResults += "" + elementsData[p].moles.toFixed(4) + " | "; detailedResults += "" + elementsData[p].ratio.toFixed(3) + " | "; detailedResults += "" + elementsData[p].wholeRatio + " | "; detailedResults += "