What is molality of ethanol in water,if molar fraction of ethanol is 0.3?

XEtOH = 0.30

XH2O = 0.70
Take enough sample to be 1 mole. That means we will have 0.3 mol EtOH and 0.7 mole H2O. How many grams H2O is that? That will be 0.70 x 18 = 12.6 g or 0.0126 kg solvent.
Then m = moles EtOH/kg solvent.

I am student

To find the molality of ethanol in water, given the molar fraction of ethanol, you can use the following steps:

Step 1: Understand the concepts
Molality (m) is defined as the moles of solute (ethanol) per kilogram of solvent (water).

Molar fraction (X) is the ratio of the moles of one component (ethanol) to the sum of the moles of all components in the mixture. It is calculated by dividing the moles of ethanol by the total moles of ethanol and water.

Step 2: Calculate the moles of ethanol
Assuming we have 1 mole of the mixture, the moles of ethanol can be calculated using the molar fraction:
moles of ethanol = molar fraction of ethanol * total moles of mixture

Step 3: Convert moles of ethanol to kilograms of water
Since the molality is expressed in moles of solute per kilogram of solvent, we need to convert the moles of ethanol to kilograms of water.

We know that the total moles of mixture (1 mole) is equal to the moles of ethanol plus the moles of water.

moles of water = total moles of mixture - moles of ethanol

Step 4: Calculate the mass of water
Now, we need to determine the mass of water in kilograms. Since 1 mole of water weighs approximately 18 grams, we can use the following conversion:

mass of water (in kg) = moles of water * molar mass of water / 1000

Step 5: Calculate molality
Finally, we can calculate the molality by dividing the moles of ethanol by the mass of water:

molality = moles of ethanol / mass of water

Following these steps, you can find the molality of ethanol in water, given the molar fraction of ethanol.

To determine the molality of ethanol in water given the molar fraction, you can follow these steps:

Step 1: Understand the concept of molality and molar fraction:
- Molality (m) is a measure of the concentration of a solute in a solution, expressed as the number of moles of the solute per kilogram of the solvent.
- Molar fraction (X) is the ratio of the number of moles of a component to the total moles of all components in a solution.

Step 2: Identify the given information:
- The molar fraction of ethanol (Xethanol) is given as 0.3 (or 30%).
- It is implied that the solvent is water.

Step 3: Calculate the molality of ethanol:
- Since molality is the ratio of moles of solute (ethanol) to the mass of the solvent (water), we need to first determine the number of moles of ethanol.
- Assume a convenient mass for the solvent, such as 1000 grams (1 kilogram) of water.
- To find the moles of ethanol, multiply the molar fraction of ethanol by the total number of moles of water.
Moles of ethanol = Xethanol * Moles of water
- The moles of water can be calculated using its molar mass, assuming 1 kilogram of water (which is equal to 1000 grams).
Moles of water = Mass of water / Molar mass of water

Step 4: Calculate the mass of ethanol:
- Use the equation m = (moles of solute) / (mass of solvent in kg)
- Rearrange the equation to solve for the mass of the solute:
Mass of solute = m * Mass of solvent
- Substitute the known values: m = moles of ethanol, Mass of solvent = 1000 grams (or 1 kilogram)

Step 5: Calculate molality:
- Using the formula molality (m) = (moles of solute) / (mass of solvent in kg), substitute the values to calculate the molality of ethanol in water.

By following these steps, you should be able to calculate the molality of ethanol in water given the molar fraction.