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 CH3CN. (c) Assuming that the volumes are additive, what is the molarity of CH 3 OH in the solution?

Hey everyone, we're told that acetone has a density of 0.7845 g per mil leader and di ethyl ether has a density of 0.7134 g per minute leader a volume of 46.5 mL of acetone is dissolved in 1 20.5 millimeter of di ethyl ether, calculate the molar concentration of acetone in the solution. Assume the volumes are additive to determine the moles of our acetone. We can go ahead and start off with our 46.5 ml of acetone And we can use our density of 0.7845 g per mil leader for our acetone. And since we want to convert this into moles, we can go ahead and use acetone moller mass, which is 58. g per one mole of acetone. Now, when we calculate this out and cancel out all our units, We end up with a total of 0.6281 mole of acetone. Now let's go ahead and calculate our volume. Since our questions them told us that the volumes are additive. We can go ahead and start off with our 46.5 mL from our acetone and we can add our 1 20.5 mL from our di ethyl ether. This will get us to 167 ml And we want to convert this into leaders and we know that we have 10-3 ml per one leader. So this gives us a total volume of 0.167 L. Now to calculate the molar concentration of acetone, we can take our 0.6 to 81 mole of acetone And we can go ahead and divide that by our total volume of 0. L. This will get us to a molar concentration of 3.76 moller, and this is going to be our final answer. So I hope this made sense and let us know if you have any questions.

Ch.13 - Properties of Solutions

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Brown 15th Edition

Ch.13 - Properties of Solutions

Problem 49c

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Chapter 13, Problem 49c

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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Calculate the mass of methanol (CH₃OH) using its volume and density: \( \text{mass} = \text{volume} \times \text{density} \).

Determine the number of moles of methanol using its molar mass: \( \text{moles} = \frac{\text{mass}}{\text{molar mass}} \).

Calculate the total volume of the solution by adding the volumes of methanol and acetonitrile: \( \text{total volume} = \text{volume of CH}_3\text{OH} + \text{volume of CH}_3\text{CN} \).

Convert the total volume from mL to L, as molarity is expressed in moles per liter.

Calculate the molarity of methanol in the solution using the formula: \( \text{Molarity} = \frac{\text{moles of CH}_3\text{OH}}{\text{total volume in L}} \).

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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 present 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.

Molarity

Molarity is a measure of concentration defined as the number of moles of solute per liter of solution (mol/L). It is an important concept in chemistry for quantifying the amount of a substance in a solution. To find the molarity of methanol in the solution, one must first calculate the number of moles of methanol and then divide by the total volume of the solution in liters.

Additivity of Volumes

The assumption of volume additivity states that when two liquids are mixed, the total volume of the resulting solution is the sum of the individual volumes of the liquids. This simplification is often used in calculations involving solutions, although it may not always hold true due to interactions between different substances. In this question, the total volume of the solution is calculated by adding the volumes of methanol and acetonitrile.

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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 (c) the molality,

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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. (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. (b) What is the molality of 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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Textbook Question

Calculate the number of moles of solute present in each of the following aqueous solutions: (b) 86.4 g of 0.180 m KCl,

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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. (c) Assuming that the volumes are additive, what is the molarity of CH3OH in the solution?

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Key Concepts

Density

Molarity

Additivity of Volumes

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?