how to determine composition of methanol-water from fractional distillation graph of temp/volume?
Just to answer myself, since I know now: get the volume of spike in temperature registered and that mL volume divide by the total volume of mixture used then multiply by 100%.
To determine the composition of methanol-water from a fractional distillation graph of temperature/volume, you need to use the concept of boiling point and the principles of fractional distillation. Here's how you can approach it:
1. Understand the basics: Fractional distillation is a process used to separate a mixture of liquids with different boiling points. In this case, methanol and water have different boiling points. Methanol boils at around 64.7 degrees Celsius, while water boils at 100 degrees Celsius at standard atmospheric pressure.
2. Analyze the graph: The fractional distillation graph of temperature/volume represents the changes in temperature as the distillation process progresses. The graph will typically show the temperature increasing as the distillation moves from the initial boiling point to the final boiling point.
3. Identify the boiling points: On the graph, locate the point where the temperature begins to rise. This is the boiling point of the lower boiling component, which in this case is methanol. Next, identify the point where the temperature plateaus or rises more slowly. This is the boiling point of the higher boiling component, which is water.
4. Calculate the composition: Measure the volume of the collected distillate and note the temperature at which it was collected. Use this information to calculate the percentage of methanol and water in the distillate. You can use a distillation table or a binary mixture phase diagram to determine the composition based on the boiling points at different temperatures.
5. Interpret the results: The composition can be expressed as a percentage of methanol and water in the distillate. For example, if the composition is 80% methanol and 20% water, that means the distillate consists of 80 parts methanol and 20 parts water.
Keep in mind that while this method provides an estimation of the composition, it is always good practice to verify the results using other analytical techniques such as refractometry or chemical analysis for greater accuracy.
To determine the composition of methanol-water from a fractional distillation graph of temperature/volume, you need to analyze the data and calculate the percentage of methanol and water at different fractions. Here's a step-by-step approach:
Step 1: Collect data
Obtain the fractional distillation graph, which consists of temperature on the y-axis and volume on the x-axis. The graph should show the temperature change as the volume increases during distillation.
Step 2: Identify key points
Identify the key points on the graph, including the boiling points of methanol and water. Methanol has a boiling point of around 64.7°C, while water boils at approximately 100°C at standard atmospheric pressure (1 atm).
Step 3: Determine the initial and final temperatures
Identify the initial temperature of the distillation process, which would be the boiling point of the mixture. This temperature corresponds to the point at which the distillation begins. Additionally, determine the final temperature, which corresponds to the boiling point of pure water.
Step 4: Locate the methanol-water fraction
Trace the graph from the initial temperature down to the final temperature. The volume at any given temperature represents the fraction of the mixture being distilled. You can use this information to calculate the composition of methanol and water at each fraction.
Step 5: Calculate the composition
For each fraction, divide the volume of methanol by the total volume at that fraction, multiply by 100, and subtract from 100 to get the percentage of water. Repeat this calculation for each fraction to determine the composition of methanol and water throughout the distillation process.
Note: This method assumes an ideal distillation process without any loss or evaporation. In practice, there may be some degree of loss or evaporation, which can affect the composition calculations.