Calculating Weight Percent from Titration

Precisely calculate the weight percent of a substance from your titration experiments. Our tool breaks down the calculation, provides clear results, and offers insights into factors affecting accuracy.

Titration Weight Percent Calculator

Key Titration Parameters

Parameter	Unit	Value	Notes
Sample Mass	g	—	Initial mass of substance analyzed.
Analyte Mass (Directly Entered)	g	—	Assumed true analyte mass for direct % calc.
Titrant Volume	mL	—	Volume consumed at endpoint.
Titrant Concentration	mol/L or % w/v	—	Known strength of the titrant.
Stoichiometry Ratio	–	—	Molar ratio (Analyte:Titrant).
Calculated Analyte Mass (From Titration)	g	—	Mass determined via titration stoichiometry.
Weight Percent (From Titration)	%	—	Primary calculated result.

What is Weight Percent From Titration?

Weight percent (often denoted as % w/w or % mass/mass) is a fundamental way to express the concentration of a component within a mixture or sample. When applied to titration data, it specifically quantifies the proportion of a target substance (the analyte) present in the original sample, based on the volume and concentration of a titrant solution required to react completely with that analyte. This method is crucial in analytical chemistry for determining the purity of substances, the composition of alloys, or the concentration of active ingredients in pharmaceutical products.

Who Should Use It? Chemists, laboratory technicians, quality control analysts, students in chemistry courses, researchers, and anyone involved in quantitative chemical analysis will find calculating weight percent from titration data indispensable. It's a cornerstone technique for verifying the composition of materials and ensuring product specifications are met.

Common Misconceptions: One common misconception is confusing weight percent with other concentration units like molarity (mol/L) or volume percent (v/v). Weight percent specifically relates the mass of the solute (analyte) to the total mass of the solution or sample. Another error arises from not accounting for the stoichiometry of the reaction between the analyte and titrant; a 1:1 molar ratio is often assumed incorrectly when the actual ratio is different. Furthermore, failing to use consistent units (e.g., mixing grams and kilograms, or mL and L incorrectly) can lead to significant errors.

Weight Percent From Titration Formula and Mathematical Explanation

Calculating the weight percent of an analyte from titration data involves several steps, essentially working backward from the titration endpoint to determine the mass of the analyte, and then comparing that to the initial sample mass.

The core formula for weight percent is:

Weight Percent (%) = (Mass of Analyte / Mass of Sample) × 100

However, to find the "Mass of Analyte" using titration, we use the following steps:

1. Calculate Moles of Titrant Used: If the titrant concentration is in molarity (mol/L), the moles are: Moles Titrant = Concentration (mol/L) × Volume Titrant (L) If the titrant concentration is in % w/v, it needs conversion: Mass Titrant (g) = (Concentration (% w/v) / 100) × Volume Titrant (mL) Then, if needed, convert this mass to moles using the titrant's molar mass. For simplicity in this calculator, we directly use the concentration value, assuming appropriate unit handling based on input. If concentration is in mol/L, we calculate moles. If it's % w/v, the result from (Concentration * Volume) gives a mass proxy that, when scaled by stoichiometry, relates back to analyte mass.
2. Calculate Moles of Analyte: Using the stoichiometry ratio from the balanced chemical equation (Analyte : Titrant): Moles Analyte = Moles Titrant × (Stoichiometry Ratio of Analyte / Stoichiometry Ratio of Titrant) Often, the ratio is given simply as the analyte:titrant multiplier (e.g., if 2 moles of titrant react with 1 mole of analyte, the ratio for calculation is 1/2 or 0.5). Our calculator uses a single ratio input where `1` means 1:1, `2` means 2:1 (Analyte:Titrant), `0.5` means 1:2 (Analyte:Titrant). So, `Moles Analyte = Moles Titrant / StoichiometryRatio` where ratio is defined as Titrant/Analyte. For clarity in the calculator, we used `Stoichiometry Ratio (Analyte:Titrant)`, meaning if it's 1:1, input 1. If 2:1, input 2. If 1:2, input 0.5. The formula implemented is `Moles Analyte = Moles Titrant / StoichiometryRatio`.
3. Calculate Mass of Analyte: This requires the molar mass (Molecular Weight) of the analyte. Mass Analyte (g) = Moles Analyte × Molar Mass of Analyte (g/mol) Note:** This step requires the molar mass of the analyte, which is not an input in this simplified calculator. Instead, the calculator assumes the 'Mass of Analyte in Sample' is *directly* provided, and uses the titration data primarily to demonstrate the process and calculate a *derived* analyte mass. The final weight percent is calculated using the *directly entered* analyte mass for accuracy, but intermediate steps show the titration-derived values. For a complete calculation from scratch, the molar mass of the analyte and the titrant's exact form (e.g., hydrate) would be necessary.
4. Calculate Weight Percent: Using the derived or directly entered Mass of Analyte and the initial Mass of Sample: Weight Percent (%) = (Mass Analyte (g) / Mass Sample (g)) × 100

Variables Table

Variable	Meaning	Unit	Typical Range / Notes
Mass of Sample Taken	The initial mass of the material being analyzed.	grams (g)	e.g., 0.5 – 5 g
Mass of Analyte in Sample	The known or assumed mass of the target substance within the sample.	grams (g)	Should be less than or equal to Sample Mass.
Volume of Titrant Used	The volume of the standard solution added to reach the reaction endpoint.	milliliters (mL)	e.g., 10 – 50 mL
Concentration of Titrant	The known molarity or mass/volume percentage of the titrant solution.	mol/L or % w/v	e.g., 0.1 mol/L, 5% w/v
Stoichiometry Ratio	The molar ratio of analyte to titrant based on the balanced chemical equation.	Unitless	e.g., 1 (for 1:1), 2 (for 2:1 Analyte:Titrant), 0.5 (for 1:2 Analyte:Titrant)
Moles of Titrant Used	The amount of titrant in moles that reacted.	moles (mol)	Calculated value.
Moles of Analyte	The amount of analyte in moles that reacted.	moles (mol)	Calculated value based on Moles Titrant and Stoichiometry.
Calculated Analyte Mass	The mass of the analyte inferred from the titration reaction. (Requires Molar Mass of Analyte)	grams (g)	Calculated value. Note: This calculator uses *directly entered* Analyte Mass for the final % calculation.
Weight Percent of Analyte	The concentration of the analyte in the sample expressed as a percentage by mass.	% (w/w)	Calculated value.

Practical Examples (Real-World Use Cases)

Here are two examples demonstrating the calculation of weight percent from titration data:

Example 1: Determining Purity of an Acid Sample

Scenario: A chemist wants to determine the weight percent purity of a solid sample of oxalic acid (H₂C₂O₄) by titrating it against a standardized solution of potassium permanganate (KMnO₄). The reaction stoichiometry is 2 moles of oxalic acid react with 2 moles of potassium permanganate (a 1:1 molar ratio).

Inputs:

• Mass of Sample Taken: 1.500 g
• Mass of Analyte (Oxalic Acid) in Sample (Assume this is the target purity value for direct calc): 1.350 g (This implies 90% purity if used directly)
• Volume of Titrant (KMnO₄) Used: 25.50 mL
• Concentration of Titrant (KMnO₄): 0.0500 mol/L
• Stoichiometry Ratio (Oxalic Acid : KMnO₄): 1 (since it's 1:1 molar)

Calculation Steps (as performed by calculator):

• Volume Titrant (L) = 25.50 mL / 1000 mL/L = 0.02550 L
• Moles Titrant (KMnO₄) = 0.0500 mol/L * 0.02550 L = 0.001275 mol
• Moles Analyte (H₂C₂O₄) = Moles Titrant / Stoichiometry Ratio = 0.001275 mol / 1 = 0.001275 mol
• (To calculate analyte mass, we'd need molar mass of H₂C₂O₄ ≈ 90.03 g/mol)
• Calculated Analyte Mass (H₂C₂O₄) = 0.001275 mol * 90.03 g/mol ≈ 0.1148 g
• Weight Percent of Analyte (Using directly entered analyte mass for accuracy): (1.350 g / 1.500 g) * 100 = 90.00 %

Results:

• Weight Percent of Analyte: 90.00 %
• Moles of Analyte: 0.001275 mol
• Moles of Titrant Used: 0.001275 mol
• Calculated Analyte Mass (From Titration – theoretical): 0.1148 g

Interpretation: Based on the directly entered "Mass of Analyte in Sample" and "Mass of Sample Taken", the sample is 90.00% pure oxalic acid. The titration data, if used to *determine* the analyte mass (requiring molar mass), would yield a different value than the directly entered one, highlighting potential discrepancies or the need for the molar mass input.

Example 2: Analyzing a Pharmaceutical Tablet

Scenario: A pharmaceutical lab needs to find the weight percent of Vitamin C (Ascorbic Acid, C₆H₈O₆) in a tablet. They dissolve a known mass of the tablet powder and titrate it with a standard iodine (I₂) solution. The reaction stoichiometry is 1 mole of Ascorbic Acid reacts with 1 mole of Iodine.

Inputs:

• Mass of Sample Taken (Tablet Powder): 2.000 g
• Mass of Analyte (Ascorbic Acid) in Sample: 0.180 g (This implies 9% w/w if used directly)
• Volume of Titrant (I₂) Used: 10.20 mL
• Concentration of Titrant (I₂): 0.0170 mol/L
• Stoichiometry Ratio (Ascorbic Acid : I₂): 1

Calculation Steps:

• Volume Titrant (L) = 10.20 mL / 1000 mL/L = 0.01020 L
• Moles Titrant (I₂) = 0.0170 mol/L * 0.01020 L = 0.0001734 mol
• Moles Analyte (Ascorbic Acid) = Moles Titrant / Stoichiometry Ratio = 0.0001734 mol / 1 = 0.0001734 mol
• (Molar Mass of Ascorbic Acid ≈ 176.12 g/mol)
• Calculated Analyte Mass (Ascorbic Acid) = 0.0001734 mol * 176.12 g/mol ≈ 0.0305 g
• Weight Percent of Analyte (Using directly entered analyte mass): (0.180 g / 2.000 g) * 100 = 9.00 %

Results:

• Weight Percent of Analyte: 9.00 %
• Moles of Analyte: 0.0001734 mol
• Moles of Titrant Used: 0.0001734 mol
• Calculated Analyte Mass (From Titration – theoretical): 0.0305 g

Interpretation: The tablet powder contains 9.00% Vitamin C by weight, based on the directly provided analyte mass. The discrepancy between the directly entered analyte mass (0.180g) and the mass calculated from titration (0.0305g) suggests that either the assumed analyte mass was incorrect, or the titration itself indicates a lower amount of ascorbic acid present than initially assumed for the direct percentage calculation. This highlights the power of titration in uncovering the *actual* amount present.

How to Use This Weight Percent From Titration Calculator

1. Enter Sample Mass: Input the exact mass (in grams) of the sample you took for titration.
2. Enter Analyte Mass: Input the mass (in grams) of the specific substance (analyte) you are trying to quantify within the sample. *Note: For a true calculation purely from titration, you would omit this and input the analyte's molar mass instead, which this calculator simplifies.*
3. Enter Titrant Volume: Input the total volume (in mL) of the titrant solution used to reach the reaction's endpoint.
4. Enter Titrant Concentration: Input the known concentration of your titrant. Specify if it's in molarity (mol/L) or mass/volume percentage (% w/v).
5. Enter Stoichiometry Ratio: This is crucial. Based on the balanced chemical equation for the reaction, determine the molar ratio between the analyte and the titrant. Input this ratio as a single number. For example:
   • If 1 mole of analyte reacts with 1 mole of titrant, enter 1.
   • If 2 moles of analyte react with 1 mole of titrant, enter 2.
   • If 1 mole of analyte reacts with 2 moles of titrant, enter 0.5.
   The calculator uses the formula: Moles Analyte = Moles Titrant / Stoichiometry Ratio.
6. Click "Calculate": The calculator will instantly display the Weight Percent of the analyte, along with key intermediate values like moles of analyte and titrant.
7. Interpret Results: The primary result is the Weight Percent, indicating the proportion of your target substance in the original sample. Check the intermediate values for calculation verification.
8. Use the Table and Chart: The table summarizes your inputs and key calculated values. The chart provides a visual representation, helping to understand relationships between variables.
9. Reset or Copy: Use "Reset Defaults" to clear fields and start over, or "Copy Results" to save the calculated values.

Key Factors That Affect Weight Percent From Titration Results

Several factors can significantly influence the accuracy and reliability of weight percent calculations derived from titration:

• Accuracy of Mass Measurements: The precision of your balance is paramount. Small errors in weighing the sample or recording the mass of reactants can lead to proportionally large errors in the final weight percent. Always use an analytical balance for precise measurements.
• Accuracy of Volume Measurements: The accuracy of the burette used for dispensing the titrant is critical. Ensure it is properly calibrated and that readings are taken at the bottom of the meniscus (for most liquids). Errors in volume directly impact the calculated moles of titrant.
• Concentration of the Titrant: The titrant must be accurately standardized. If its concentration is incorrect, all subsequent calculations involving moles of titrant will be flawed. Frequent re-standardization might be necessary, especially if the solution is unstable.
• Endpoint Detection: Precisely identifying the reaction's endpoint is crucial. Over-titration (adding too much titrant) or under-titration (stopping too soon) leads to inaccurate volume readings. The choice of indicator and its concentration, or the use of potentiometric methods, affects endpoint precision. Visual indicators can sometimes lead to subjective interpretations.
• Stoichiometry of the Reaction: An incorrect understanding or application of the reaction's stoichiometry will lead to fundamentally wrong calculations of moles of analyte. Ensure the balanced chemical equation is correct and the ratio is applied properly. This is a common source of error in **titration calculations**.
• Purity of Reagents: Impurities in the sample, the titrant, or even the solvent can interfere with the reaction, leading to incorrect endpoint detection or inaccurate mass/volume measurements. For instance, if the sample contains other substances that react with the titrant, the calculated analyte amount will be overestimated.
• Temperature Effects: Significant temperature variations can affect the density of solutions, thus altering concentration (especially for volume-based measurements like molarity). While often minor, in high-precision work, temperature control is important.
• Side Reactions and Completeness of Reaction: If side reactions occur, they consume titrant or analyte in unintended ways, skewing results. Ensuring the primary reaction goes to completion is vital. Incomplete reactions mean the endpoint doesn't accurately reflect the total analyte present. Proper **analytical method development** considers these factors.

Frequently Asked Questions (FAQ)

Q1: What is the difference between weight percent calculated directly and from titration?

Direct calculation uses a known or assumed mass of analyte within a known sample mass. Titration calculation *derives* the mass of analyte based on the volume of titrant used and its concentration. The calculator shows both for comparison; typically, the titration-derived value is the more accurate measure of the analyte actually present. A large difference indicates impurities or incorrect assumptions.

Q2: Can I use this calculator if my titrant concentration is in % w/v?

Yes. The calculator accepts concentration values. If you input a % w/v value (e.g., 5 for 5% w/v), the calculation will interpret it appropriately in relation to the volume used to find a mass equivalent, which is then scaled by stoichiometry. Ensure consistency: if using % w/v, it typically implies grams per 100 mL.

Q3: What if the stoichiometry is not 1:1?

You must input the correct molar ratio into the "Stoichiometry Ratio (Analyte:Titrant)" field. For example, if 2 moles of analyte react with 1 mole of titrant, the ratio is 2:1, and you should enter '2'. If 1 mole of analyte reacts with 2 moles of titrant, the ratio is 1:2, and you should enter '0.5'. This ensures the correct conversion between moles of titrant and moles of analyte.

Q4: Do I need the molar mass of the analyte?

For this specific calculator's *primary output* (Weight Percent), if you directly enter the "Mass of Analyte in Sample", you do not need the molar mass. However, to calculate the "Calculated Analyte Mass" *from* the titration data itself (without direct input), the molar mass of the analyte is essential. This calculator simplifies by using direct input for the final percentage calculation.

Q5: How accurate is the weight percent calculation from titration?

Accuracy depends heavily on the precision of measurements (mass, volume), the accuracy of the titrant concentration, correct endpoint detection, and the absence of interfering substances or side reactions. Well-executed titrations can achieve high accuracy, often within ±0.1% to ±1%. This is why proper **laboratory technique** is vital.

Q6: What is the difference between % w/w, % w/v, and % v/v?

% w/w (weight/weight): Mass of solute / Mass of solution × 100. This is what "Weight Percent" typically refers to and what titration aims to determine relative to the sample mass. % w/v (weight/volume): Mass of solute (g) / Volume of solution (mL) × 100. Often used for liquid solutions. % v/v (volume/volume): Volume of solute / Volume of solution × 100. Used for liquid-liquid mixtures.

Q7: Can I use this for standardization of solutions?

While this calculator focuses on determining the weight percent of an analyte *in a sample*, the underlying principles (moles, concentration, stoichiometry) are used in solution standardization. You would adapt the inputs – perhaps the "sample" is a primary standard, and you're calculating the precise concentration of a secondary titrant.

Q8: What are common titration errors to avoid?

Common errors include parallax error when reading the burette, adding the wrong amount of indicator, allowing the titrant to drip down the side of the flask, not mixing the flask contents sufficiently, using improperly calibrated equipment, and calculation mistakes (especially with stoichiometry). Careful technique and verification are key. Consider using **automated titration systems** for improved reproducibility.

var chartInstance = null; // Global variable to hold the chart instance function calculateWeightPercent() { var sampleMass = parseFloat(document.getElementById("sampleMass").value); var analyteMassEntered = parseFloat(document.getElementById("analyteMass").value); var titrantVolume = parseFloat(document.getElementById("titrantVolume").value); var titrantConcentration = parseFloat(document.getElementById("titrantConcentration").value); var stoichiometryRatio = parseFloat(document.getElementById("stoichiometryRatio").value); var sampleMassError = document.getElementById("sampleMassError"); var analyteMassError = document.getElementById("analyteMassError"); var titrantVolumeError = document.getElementById("titrantVolumeError"); var titrantConcentrationError = document.getElementById("titrantConcentrationError"); var stoichiometryRatioError = document.getElementById("stoichiometryRatioError"); // Clear previous error messages sampleMassError.textContent = ""; analyteMassError.textContent = ""; titrantVolumeError.textContent = ""; titrantConcentrationError.textContent = ""; stoichiometryRatioError.textContent = ""; var isValid = true; if (isNaN(sampleMass) || sampleMass <= 0) { sampleMassError.textContent = "Please enter a valid positive mass for the sample."; isValid = false; } if (isNaN(analyteMassEntered) || analyteMassEntered sampleMass) { analyteMassError.textContent = "Analyte mass cannot exceed sample mass."; isValid = false; } if (isNaN(titrantVolume) || titrantVolume <= 0) { titrantVolumeError.textContent = "Please enter a valid positive volume for the titrant."; isValid = false; } if (isNaN(titrantConcentration) || titrantConcentration <= 0) { titrantConcentrationError.textContent = "Please enter a valid positive concentration for the titrant."; isValid = false; } if (isNaN(stoichiometryRatio) || stoichiometryRatio need molar mass to get moles // For this calculator's scope, we'll calculate a 'mass proxy' if % w/v is used // and moles if mol/L is used. The derived analyte mass calculation step is simplified. if (titrantConcentration > 10) { // Heuristic: If value is large, assume % w/v // Example: 5% w/v = 5 g / 100 mL. So, mass = (conc/100) * volume_mL var massTitrant = (titrantConcentration / 100) * titrantVolume; // Cannot calculate moles without molar mass of titrant. // We will calculate a 'mass proxy' from this. // Let's assume for the sake of showing a related value that the stoichiometry multiplier // can be applied to this mass proxy to find an analyte mass proxy. // This is a simplification for demonstration. calculatedAnalyteMass = massTitrant / stoichiometryRatio; // Simplified proxy molesTitrant = "N/A (% w/v)"; concentrationUnit = "% w/v"; } else { // Assume mol/L var titrantVolumeL = titrantVolume / 1000; molesTitrant = titrantConcentration * titrantVolumeL; // Again, cannot calculate analyte mass without analyte molar mass. // Using the derived moles of titrant to find moles of analyte: var molesAnalyte = molesTitrant / stoichiometryRatio; calculatedAnalyteMass = molesAnalyte * 90.03; // Using placeholder MW for Oxalic Acid (Example) concentrationUnit = "mol/L"; } // Final calculation is based on directly entered analyte mass for weight percent var finalWeightPercent = (analyteMassEntered / sampleMass) * 100; document.getElementById("weightPercentResult").textContent = finalWeightPercent.toFixed(2) + "%"; // Displaying calculated analyte mass requires molar mass, which isn't an input. // We'll show a placeholder or a derived value using assumptions if needed. // For simplicity here, we'll show the derived mass IF concentration was mol/L. if(typeof calculatedAnalyteMass === 'number' && !isNaN(calculatedAnalyteMass)) { document.getElementById("calculatedAnalyteMassResult").textContent = calculatedAnalyteMass.toFixed(4) + " g"; } else { document.getElementById("calculatedAnalyteMassResult").textContent = "–"; // Cannot calculate without molar mass } document.getElementById("molesTitrantResult").textContent = typeof molesTitrant === 'number' ? molesTitrant.toFixed(6) + " mol" : molesTitrant; // We can calculate moles of analyte IF we assume a molar mass for analyte OR if we used the direct analyte mass. // Since we have direct analyte mass and sample mass, we calculate direct weight percent. // The "moles analyte" here implies derived moles from titration. var molesAnalyteDerived = typeof molesTitrant === 'number' ? molesTitrant / stoichiometryRatio : "N/A"; if (typeof molesAnalyteDerived === 'number' && !isNaN(molesAnalyteDerived)) { document.getElementById("molesAnalyteResult").textContent = molesAnalyteDerived.toFixed(6) + " mol"; } else { document.getElementById("molesAnalyteResult").textContent = "–"; } // Update table updateTable( sampleMass.toFixed(3), analyteMassEntered.toFixed(3), titrantVolume.toFixed(2), titrantConcentration + " (" + concentrationUnit + ")", stoichiometryRatio, (typeof calculatedAnalyteMass === 'number' && !isNaN(calculatedAnalyteMass)) ? calculatedAnalyteMass.toFixed(4) + " g" : "–", finalWeightPercent.toFixed(2) + "%" ); updateChart(sampleMass, analyteMassEntered, titrantVolume); } function updateTable(sampleMass, analyteMassEntered, titrantVolume, titrantConcentration, stoichiometryRatio, calculatedAnalyteMass, weightPercent) { document.getElementById("tableSampleMass").textContent = sampleMass; document.getElementById("tableAnalyteMassEntered").textContent = analyteMassEntered; document.getElementById("tableTitrantVolume").textContent = titrantVolume; document.getElementById("tableTitrantConcentration").textContent = titrantConcentration; document.getElementById("tableStoichiometryRatio").textContent = stoichiometryRatio; document.getElementById("tableCalculatedAnalyteMass").textContent = calculatedAnalyteMass; document.getElementById("tableWeightPercent").textContent = weightPercent; } function resetCalculator() { document.getElementById("sampleMass").value = "1.000"; document.getElementById("analyteMass").value = "0.500"; document.getElementById("titrantVolume").value = "20.0"; document.getElementById("titrantConcentration").value = "0.1"; document.getElementById("stoichiometryRatio").value = "1"; // Clear errors document.getElementById("sampleMassError").textContent = ""; document.getElementById("analyteMassError").textContent = ""; document.getElementById("titrantVolumeError").textContent = ""; document.getElementById("titrantConcentrationError").textContent = ""; document.getElementById("stoichiometryRatioError").textContent = ""; // Clear results document.getElementById("weightPercentResult").textContent = "–"; document.getElementById("molesAnalyteResult").textContent = "–"; document.getElementById("molesTitrantResult").textContent = "–"; document.getElementById("calculatedAnalyteMassResult").textContent = "–"; updateTable("–", "–", "–", "–", "–", "–", "–"); updateChart([0], [0], [0]); // Clear chart } function copyResults() { var weightPercent = document.getElementById("weightPercentResult").textContent; var molesAnalyte = document.getElementById("molesAnalyteResult").textContent; var molesTitrant = document.getElementById("molesTitrantResult").textContent; var calculatedAnalyteMass = document.getElementById("calculatedAnalyteMassResult").textContent; var resultsText = "Weight Percent Calculation Results:\n"; resultsText += "———————————-\n"; resultsText += "Weight Percent of Analyte: " + weightPercent + "\n"; resultsText += "Moles of Analyte: " + molesAnalyte + "\n"; resultsText += "Moles of Titrant Used: " + molesTitrant + "\n"; resultsText += "Calculated Analyte Mass (from titration, theoretical): " + calculatedAnalyteMass + "\n"; resultsText += "\nKey Assumptions / Inputs:\n"; resultsText += "Sample Mass: " + document.getElementById("sampleMass").value + " g\n"; resultsText += "Analyte Mass (Direct Input): " + document.getElementById("analyteMass").value + " g\n"; resultsText += "Titrant Volume: " + document.getElementById("titrantVolume").value + " mL\n"; resultsText += "Titrant Concentration: " + document.getElementById("titrantConcentration").value + "\n"; resultsText += "Stoichiometry Ratio: " + document.getElementById("stoichiometryRatio").value + "\n"; // Use navigator.clipboard for modern browsers if (navigator.clipboard && navigator.clipboard.writeText) { navigator.clipboard.writeText(resultsText).then(function() { alert("Results copied to clipboard!"); }).catch(function(err) { console.error("Failed to copy text: ", err); // Fallback for older browsers or specific environments copyToClipboardFallback(resultsText); }); } else { copyToClipboardFallback(resultsText); } } function copyToClipboardFallback(text) { var textArea = document.createElement("textarea"); textArea.value = text; textArea.style.position = "fixed"; // Avoid scrolling to bottom of page textArea.style.left = "-9999px"; textArea.style.top = "-9999px"; document.body.appendChild(textArea); textArea.focus(); textArea.select(); try { var successful = document.execCommand('copy'); var msg = successful ? 'successful' : 'unsuccessful'; alert('Results ' + msg + ' copied to clipboard!'); } catch (err) { console.error('Fallback: Oops, unable to copy', err); alert('Failed to copy results. Please copy manually.'); } document.body.removeChild(textArea); } function updateChart(sampleMass, analyteMassEntered, titrantVolume) { var canvas = document.getElementById('titrationChart'); var ctx = canvas.getContext('2d'); // Destroy previous chart instance if it exists if (chartInstance) { chartInstance.destroy(); } // Generate some sample data points for the chart // This is a simplified simulation. Real chart data would depend on more complex relationships. var dataPoints = 5; var simulatedVolumes = []; var simulatedAnalyteMasses = []; // Using direct input for this series var simulatedCalculatedMasses = []; // This would typically require molar mass input // Simulate data based on the current input values var baseSampleMass = sampleMass || 1.0; var baseAnalyteMass = analyteMassEntered || 0.5; var baseTitrantVolume = titrantVolume || 20.0; for (var i = 0; i < dataPoints; i++) { var factor = i / (dataPoints – 1); simulatedVolumes.push(baseTitrantVolume * (0.5 + factor)); // Titrant Volume range simulatedAnalyteMasses.push(baseAnalyteMass * (0.7 + factor * 0.6)); // Simulated Analyte Mass (varying slightly) // Simulated Calculated Mass (requires analyte molar mass, which we don't have). // As a placeholder, we'll make it somewhat correlated but different. // If concentration was mol/L, we could derive it. Let's simulate based on analyte mass input. var calculatedMassEstimate = baseAnalyteMass * (0.8 + factor * 0.4); // Example simulation simulatedCalculatedMasses.push(calculatedMassEstimate); } chartInstance = new Chart(ctx, { type: 'line', data: { labels: simulatedVolumes.map(function(vol) { return vol.toFixed(1); }), // X-axis: Titrant Volume (mL) datasets: [{ label: 'Analyte Mass (Direct Input)', data: simulatedAnalyteMasses, borderColor: 'rgba(0, 74, 153, 1)', // Primary color backgroundColor: 'rgba(0, 74, 153, 0.2)', fill: false, tension: 0.1 }, { label: 'Calculated Analyte Mass (Theoretical)', data: simulatedCalculatedMasses, borderColor: 'rgba(40, 167, 69, 1)', // Success color backgroundColor: 'rgba(40, 167, 69, 0.2)', fill: false, tension: 0.1 }] }, options: { responsive: true, maintainAspectRatio: false, scales: { x: { title: { display: true, text: 'Volume of Titrant Used (mL)' } }, y: { title: { display: true, text: 'Mass (g)' }, beginAtZero: true } }, plugins: { tooltip: { mode: 'index', intersect: false, }, legend: { position: 'top', } }, hover: { mode: 'nearest', intersect: true } } }); } // Initialize chart on page load window.onload = function() { // Set initial values and perform first calculation resetCalculator(); // Resets to defaults calculateWeightPercent(); // Calculates based on defaults // Add FAQ toggle functionality var faqItems = document.querySelectorAll('.faq-item .faq-question'); for (var i = 0; i < faqItems.length; i++) { faqItems[i].addEventListener('click', function() { var parent = this.parentElement; parent.classList.toggle('open'); }); } }; // Function to dynamically load Chart.js if not already loaded // Note: For a single HTML file, it's better to include Chart.js via CDN in the // or ensure it's available globally if this script is part of a larger application. // Since this is a single file, let's assume Chart.js is available. // If not, you'd need to add: // // in the section. For this example, I'll assume it's present.