The density of acetonitrile (CH 3 CN) is 0.786 g/mL and the density of methanol (CH 3 OH) is 0.791 g/mL. A solution is made by dissolving 22.5 mL of CH 3 OH in 98.7 mL of CH 3 CN. (b) What is the molality of the solution?

First, we need to calculate the mass of each component. The mass of a substance can be calculated by multiplying its volume by its density. So, calculate the mass of CH 3 CN and CH 3 OH using their respective volumes and densities.. Next, convert the mass of CH 3 OH to moles. The molar mass of CH 3 OH is approximately 32.04 g/mol. Divide the mass of CH 3 OH by its molar mass to get the number of moles.. Molality is defined as the number of moles of solute (in this case, CH 3 OH) per kilogram of solvent (in this case, CH 3 CN). Convert the mass of CH 3 CN from grams to kilograms by dividing by 1000.. Finally, calculate the molality by dividing the number of moles of CH 3 OH by the mass of CH 3 CN in kilograms. This will give you the molality of the solution in mol/kg.. Remember that molality is a measure of the concentration of a solution. It tells us how many moles of solute are present in a certain amount of solvent. In this case, it tells us how many moles of methanol are present in a certain amount of acetonitrile.

The density of acetonitrile (CH 3 CN) is 0.786 g/mL and the density of methanol (CH 3 OH) is 0.791 g/mL. A solution is made by dissolving 22.5 mL of CH 3 OH in 98.7 mL of CH 3 CN. (b) What is the molality of the solution?

Everyone here acts at 25°C. What is the morality of associate prepared by dissolving? 32.6 ml of ethanol, 250 millions of water. And it has a final solution volume of 275 ml. Given the density of ethanol and the density of water. Recall that morality m It was the malls of the salute. Bye bye kilograms of a solvent. I need the first time the most of the so you have 32.6 ml at an all. We have the density of Ethanol, which is 0.789 g per male leader. And in one wall of ethanol at the Mueller mass. And this is two times 12.011 g a six I was 1.008 g Plus 15.999 g. We're gonna get 46 07 g. That's gonna give us 0.55 83 balls. So now we need to find the mass of the solvent. 250 ml. You have the density of water, which is one g male leader in one kg Of 1000 g. And this gives us 0.25 telegrams. So now we can put these bags into the equation, we're gonna get em was 0. 83 walls By 0.25 telegrams. So the morality gonna be 2.23. Thanks for watching my video. And I hope it was helpful

Ch.13 - Properties of Solutions

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Brown 15th Edition

Ch.13 - Properties of Solutions

Problem 49b

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Chapter 13, Problem 49b

The density of acetonitrile (CH₃CN) is 0.786 g/mL and the density of methanol (CH₃OH) is 0.791 g/mL. A solution is made by dissolving 22.5 mL of CH₃OH in 98.7 mL of CH₃CN. (b) What is the molality of the solution?

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First, we need to calculate the mass of each component. The mass of a substance can be calculated by multiplying its volume by its density. So, calculate the mass of CH3CN and CH3OH using their respective volumes and densities.

Next, convert the mass of CH3OH to moles. The molar mass of CH3OH is approximately 32.04 g/mol. Divide the mass of CH3OH by its molar mass to get the number of moles.

Molality is defined as the number of moles of solute (in this case, CH3OH) per kilogram of solvent (in this case, CH3CN). Convert the mass of CH3CN from grams to kilograms by dividing by 1000.

Finally, calculate the molality by dividing the number of moles of CH3OH by the mass of CH3CN in kilograms. This will give you the molality of the solution in mol/kg.

Remember that molality is a measure of the concentration of a solution. It tells us how many moles of solute are present in a certain amount of solvent. In this case, it tells us how many moles of methanol are present in a certain amount of acetonitrile.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Density

Density is defined as mass per unit volume and is typically expressed in grams per milliliter (g/mL) for liquids. It is a crucial property that helps determine how much mass of a substance is contained in a given volume. In this question, the densities of acetonitrile and methanol are provided, which will be used to calculate the mass of each component in the solution.

Molality

Molality is a measure of concentration defined as the number of moles of solute per kilogram of solvent. It is particularly useful in situations where temperature changes may affect volume, as it relies on mass rather than volume. To calculate molality, one must first determine the moles of methanol and the mass of the solvent (acetonitrile) in kilograms.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is essential for converting between grams and moles when performing calculations in chemistry. In this problem, the molar mass of methanol will be needed to convert the mass of methanol into moles, which is necessary for calculating the molality of the solution.

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Molar Mass Concept

Related Practice

Ascorbic acid (vitamin C, C₆H₈O₆) is a water-soluble vitamin. A solution containing 80.5 g of ascorbic acid dissolved in 210 g of water has a density of 1.22 g/mL at 55 °C. Calculate (a) the mass percentage,

The density of acetonitrile (CH₃CN) is 0.786 g/mL and the density of methanol (CH₃OH) is 0.791 g/mL. A solution is made by dissolving 22.5 mL of CH₃OH in 98.7 mL of CH₃CN. (a) What is the mole fraction of methanol in the solution?

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Textbook Question

The density of acetonitrile (CH₃CN) is 0.786 g/mL and the density of methanol (CH₃OH) is 0.791 g/mL. A solution is made by dissolving 22.5 mL of CH₃OH in 98.7 mL of CH3CN. (c) Assuming that the volumes are additive, what is the molarity of CH₃OH in the solution?

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Textbook Question

The density of toluene (C₇H₈) is 0.867 g/mL, and the density of thiophene (C₄H₄S) is 1.065 g/mL. A solution is made by dissolving 8.10 g of thiophene in 250.0 mL of toluene. (a) Calculate the mole fraction of thiophene in the solution.

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Textbook Question

The density of toluene (C₇H₈) is 0.867 g/mL, and the density of thiophene (C₄H₄S) is 1.065 g/mL. A solution is made by dissolving 8.10 g of thiophene in 250.0 mL of toluene. (b) Calculate the molality of thiophene in the solution.

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The density of acetonitrile (CH3CN) is 0.786 g/mL and the density of methanol (CH3OH) is 0.791 g/mL. A solution is made by dissolving 22.5 mL of CH3OH in 98.7 mL of CH3CN. (b) What is the molality of the solution?

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Key Concepts

Density

Molality

Molar Mass

The density of acetonitrile (CH₃CN) is 0.786 g/mL and the density of methanol (CH₃OH) is 0.791 g/mL. A solution is made by dissolving 22.5 mL of CH₃OH in 98.7 mL of CH₃CN. (b) What is the molality of the solution?