Answered: Calculate the molality, molarity, and…

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

See similar textbooks

Related questions

Concept explainers

Question

Calculate the molality, molarity, and mole fraction of FeCl₃ in a 28.8 mass % aqueous solution (d=1.280 g/mL).

Expert Solution

Step 1

Molarity is equal to the number of moles of solute dissolved per liter of solution. It is denoted by M. Its SI unit is mol/L. Molality is equal to the number of moles of solute dissolved per kg of solvent. It is denoted by m. Its SI unit is mol/kg. Mole fraction is equal to the number of moles of the given substance to the total moles of the substance. It is unitless. The formula for calculating molarity, morality, and mole fraction is shown below.

$\begin{array}{rcl} Molarity & = & \frac{Mass}{Molar mass} \times \frac{1000}{Volume} . \\ Molality & = & \frac{Mass}{Molar mass} \times \frac{1000}{Mass of solvent} . \\ Mole fraction & = & \frac{Number of moles of the given substance}{Total number of moles of the substance} . \end{array}$

Step 2

a)To determine the molarity.

Data given

Mass % of soluion=28.8 %.

Density=1.280 g/mL.

Mass of FeCl₃=28.8 g.

Mass of solvent=71.2 g.

Mass of solution=100 g.

The molar mass of FeCl₃=162.2 g/mol.

To determine the molarity of the solution.

$\begin{array}{rcl} Density & = & \frac{Mass}{Volume} . \\ 1.280 g / mL & = & \frac{100 g}{Volume} . \\ Volume & = & \frac{100 g}{1.280 g / mL} . \\ Volume & = & 78.125 mL . \end{array}$

Molarity of the solution.

$Molarity = \frac{Mass}{Molar mass} \times \frac{1000}{Volume of solution} . Molarity = \frac{28.8 g}{162.2 g / mol} \times \frac{1000}{78.125 mL} . Molarity = 2.27 M .$

Step 3

b)To determine the molality.

$Molality = \frac{Mass}{Molality} \times \frac{1000}{Mass of solvent} . Molality = \frac{28.8 g}{162.2 g / mol} \times \frac{1000}{71.2 g} . Molality = 2.49 m .$

Step by step

Solved in 5 steps

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.

Similar questions