Ch.12 - SolutionsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Problem

What mass in grams of a molecular substance (molar mass = 50.0 g/mol) must be added to 500 g of water to produce a solution that boils at 101.02 °C? (Kbp = 0.512 °C/m for water.)

a. 43 g

b. 50 g

c. 78 g

d. 92 g

e.  112g


Solution

We’re being asked to determine the mass of an unknown compound with a molar mass of 50 g/mol if the boiling point of the aqueous solution is 101.02 ˚C

For this problem, we have to follow the steps:

Step 1. Establish the necessary equations

Step 2. Calculate for molality

Step 3.  Calculate for mass


Step 1. Recall that the boiling point of a solution is higher than that of the pure solvent and the change in boiling point (ΔT­b) is given by:

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