Thermochemical Analysis of the Devil's Milkshake

Analysis of Devil's Milkshake

A year ago I stumbled across a fun way to present the reaction between calcium metal and water. Check it out (including a video explanation): .

Ca(s) + H2O(l) à CaO(s) + H2(g)                             Equation 1

It is very easy to carry out the reaction. Simply add calcium metal to water, wait for bubbles to form, and then light the ensuing bubbles on fire. The bubbles are filled with hydrogen gas, which react with oxygen in the atmosphere to form water:

2 H2(g) + O2(g) à 2 H2O(g)                                      Equation 2

The formation of calcium oxide causes the contents of the water to turn a milky white color. This color change, coupled with the fiery bubbles at the top of the fluid prompted the nickname of “The Devil’s Milkshake” for this reaction. I find it to be a great experiment for the Halloween season.

It turns out it is very simple to use this reaction to estimate the enthalpy of the reaction between calcium metal and water (Equation 1). By doing so you can introduce your students to quantitative concepts in thermochemistry. You can see how I have done this in the video below.

Video 1: , Tommy Technicium YouTube Channel, 10/28/2020

 

As you can see, the heat equation (Q = mcT), enthalpy of reaction, and standard enthalpy of formation are all topics that are touched upon in this presentation. This experiment is simple enough that I think students can perform it on their own as a laboratory experiment. If doing so, it should be stressed that the hydrogen gas generated in this experiment reacts explosively with atmospheric oxygen. As a result, flames must be kept away from the reaction as it proceeds.

Happy Halloween!

 

Safety

General Safety

For Laboratory Work: Please refer to the ACS .  

For Demonstrations: Please refer to the ACS Division of Chemical Education .

Other Safety resources

: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies

 

Safety: Video Demonstration

Demonstration videos presented here are not meant as tools to teach chemical demonstration techniques. They are meant as a tool for classroom use. The demonstrations may present safety hazards or show phenomena that are difficult for an entire class to observe in a live demonstration.

Those performing the demonstrations shown in this video have been trained and adhere to best safety practices.

Anyone thinking about performing a chemistry demonstration should first read and then adhere to the  These guidelines are also available at ChemEd X.

NGSS

Analyzing data in 9–12 builds on K–8 and progresses to introducing more detailed statistical analysis, the comparison of data sets for consistency, and the use of models to generate and analyze data.

Summary:

Analyzing data in 9–12 builds on K–8 and progresses to introducing more detailed statistical analysis, the comparison of data sets for consistency, and the use of models to generate and analyze data. Analyze data using tools, technologies, and/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims or determine an optimal design solution.

Assessment Boundary:
Clarification:

Planning and carrying out investigations in 9-12 builds on K-8 experiences and progresses to include investigations that provide evidence for and test conceptual, mathematical, physical, and empirical models.

Summary:

Planning and carrying out investigations in 9-12 builds on K-8 experiences and progresses to include investigations that provide evidence for and test conceptual, mathematical, physical, and empirical models. Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements and consider limitations on the precision of the data (e.g., number of trials, cost, risk, time), and refine the design accordingly.

Assessment Boundary:
Clarification:

Mathematical and computational thinking at the 9–12 level builds on K–8 and progresses to using algebraic thinking and analysis, a range of linear and nonlinear functions including trigonometric functions, exponentials and logarithms, and computational tools for statistical analysis to analyze, represent, and model data. Simple computational simulations are created and used based on mathematical models of basic assumptions. Use mathematical representations of phenomena to support claims.

Summary:

Mathematical and computational thinking at the 9–12 level builds on K–8 and progresses to using algebraic thinking and analysis, a range of linear and nonlinear functions including trigonometric functions, exponentials and logarithms, and computational tools for statistical analysis to analyze, represent, and model data. Simple computational simulations are created and used based on mathematical models of basic assumptions. Use mathematical representations of phenomena to support claims.

Assessment Boundary:
Clarification:

Students who demonstrate understanding can use a model to describe how variations in the flow of energy into and out of Earth’s systems result in changes in climate.

More information about all DCI for HS-ESS2 can be found  and further resources at .

Summary:

Students who demonstrate understanding can use a model to describe how variations in the flow of energy into and out of Earth’s systems result in changes in climate.

Assessment Boundary:

Assessment of the results of changes in climate is limited to changes in surface temperatures, precipitation patterns, glacial ice volumes, sea levels, and biosphere distribution.

Clarification:

Examples of the causes of climate change differ by timescale, over 1-10 years: large volcanic eruption, ocean circulation; 10-100s of years: changes in human activity, ocean circulation, solar output; 10-100s of thousands of years: changes to Earth's orbit and the orientation of its axis; and 10-100s of millions of years: long-term changes in atmospheric composition.

Students who demonstrate understanding can develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy.

*More information about all DCI for HS-PS1 can be found at  and further resources at .

Summary:

Students who demonstrate understanding can develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy.

Assessment Boundary:

Assessment does not include calculating the total bond energy changes during a chemical reaction from the bond energies of reactants and products.

Clarification:

Emphasis is on the idea that a chemical reaction is a system that affects the energy change. Examples of models could include molecular-level drawings and diagrams of reactions, graphs showing the relative energies of reactants and products, and representations showing energy is conserved.

Energy help students formulate an answer to the question, “How is energy transferred and conserved?” The Core Idea expressed in the Framework for PS3 is broken down into four sub-core ideas: Definitions of Energy, Conservation of Energy and Energy Transfer, the Relationship between Energy and Forces, and Energy in Chemical Process and Everyday Life. Energy is understood as quantitative property of a system that depends on the motion and interactions of matter and radiation within that system, and the total change of energy in any system is always equal to the total energy transferred into or out of the system. Students develop an understanding that energy at both the macroscopic and the atomic scale can be accounted for as either motions of particles or energy associated with the configuration (relative positions) of particles. In some cases, the energy associated with the configuration of particles can be thought of as stored in fields. Students also demonstrate their understanding of engineering principles when they design, build, and refine devices associated with the conversion of energy. The crosscutting concepts of cause and effect; systems and system models; energy and matter; and the influence of science, engineering, and technology on society and the natural world are further developed in the performance expectations associated with PS3. In these performance expectations, students are expected to demonstrate proficiency in developing and using models, planning and carry out investigations, using computational thinking and designing solutions; and to use these practices to demonstrate understanding of the core ideas.*

*More information about all DCI for HS-PS3 can be found at 

Summary:

Energy help students formulate an answer to the question, “How is energy transferred and conserved?” The Core Idea expressed in the Framework for PS3 is broken down into four sub-core ideas: Definitions of Energy, Conservation of Energy and Energy Transfer, the Relationship between Energy and Forces, and Energy in Chemical Process and Everyday Life. Energy is understood as quantitative property of a system that depends on the motion and interactions of matter and radiation within that system, and the total change of energy in any system is always equal to the total energy transferred into or out of the system. Students develop an understanding that energy at both the macroscopic and the atomic scale can be accounted for as either motions of particles or energy associated with the configuration (relative positions) of particles. In some cases, the energy associated with the configuration of particles can be thought of as stored in fields. Students also demonstrate their understanding of engineering principles when they design, build, and refine devices associated with the conversion of energy. The crosscutting concepts of cause and effect; systems and system models; energy and matter; and the influence of science, engineering, and technology on society and the natural world are further developed in the performance expectations associated with PS3. In these performance expectations, students are expected to demonstrate proficiency in developing and using models, planning and carry out investigations, using computational thinking and designing solutions; and to use these practices to demonstrate understanding of the core ideas

Assessment Boundary:
Clarification:

Students who demonstrate understanding can create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.

*More information about all DCI for HS-PS3 can be found at 

Summary:

Students who demonstrate understanding can create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.

Assessment Boundary:

Assessment is limited to basic algebraic expressions or computations; to systems of two or three components; and to thermal energy, kinetic energy, and/or the energies in gravitational, magnetic, or electric fields.

Clarification:

Emphasis is on explaining the meaning of mathematical expressions used in the model.