Ch.3 - Chemical ReactionsWorksheetSee 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

Solution: Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide:                CaO (s) + H2O  (l) → Ca(OH)2 (s)In a particular experiment, a 1.50 g sample of CaO is reacted wit

Problem

Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide:

                CaO (s) + H2O  (l) → Ca(OH)2 (s)

In a particular experiment, a 1.50 g sample of CaO is reacted with 1.50 kg of water and 1.48 g of Ca(OH)2 is recovered. What is the percent yield in this experiment?

A. 99.0%
B. 24.0%
C. 2.16%
D. 74.8%
E. 101.2%


Solution

We’re being asked to calculate the percent yield of Ca(OH)2 in the reaction of 1.50 g CaO with excess H2O. The balanced chemical equation is:

CaO(s) + H2O(l)  Ca(OH)2(s)


Recall that percent yield is given by:

%yield = actual yieldtheoretical yield x 100


We know the reaction produced 1.48 g Ca(OH)2; this is the actual yield of the reaction. To calculate the theoretical yield, we need to do the following:


Mass of CaO (molar mass of CaO)  Moles of CaO (mole-to-mole comparison)  Moles of Ca(OH)2 (molar mass of Ca(OH)2)  Mass of Ca(OH)2


Since H2O is in excess, we can simply ignore it in our calculations.

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