Web Activity: Web Quest⎯Rocket Fuel Thermochemistry page 513 The history of rocketry is longer than most people think. Throughout time various formulations of rocket propellant have been developed. As early as 200 B.C.E., humankind developed technology such as gunpowder. Centuries of continual research and discovery led to the advanced rocket technology that took humans to the Moon, and robots to Mars. Modern rocket engines vary in design, depending on the type of fuel (solid or liquid) used. There are pros and cons for each type of engine. Currently, many modern launching systems, such as the Space Shuttle and Atlas V rocket, use a combination of liquid- and solid-fuel rocket motors – exploiting the strengths of each design to help get them into space. Criteria to be considered include, but are not limited to, safety, reliability, environmental impact, and cost. Task A team of aerospace engineers is working on a plan to design, build, and test a reuseable rocket, with a large payload capacity, designed for space travel. The team is considering which fuel will best meet the rocket’s needs, and wants your research group’s expert input. They have asked your group to research the four fuels listed in Table 1. The engineers will use your findings when designing their rocket. Table 1: Reference Data for Selected Fuel Reactions Fuel Reaction Reactant

or product Thermochemical data

ammonium perchlorate

H∆4 4

f mNH ClO (s)

= -295.8 kJ/mol° 3 →4 4 2 3 3 2 Al(s) + 3 NH ClO (s) Al O (s) + AlCl (s) + 3 NO(g) + 6 H O(g)

aluminium chloride f H∆

3

mAlCl (s)

= -705.6 kJ/mol°

hydrogen →2 21

2 2H (g) + O (g) H O(g) oxygen monomethyl hydrazine

H∆3 2

f mCH NHNH (l)

= -54.1 kJ/mol° →3 2 2 4 2 2 24 CH NHNH (l) + 5 N O (l) 5 N (g) + 4 CO (g) + 12 H O(g)

dinitrogen tetroxide

H∆2 4

f mN O (l)

= -19.6 kJ/mol°

→12 26 2 2 2C H (l) + O (g) CO (g) + H O(g) (unbalanced reaction) n-dodecane H∆12 26

f mC H (l)

= -291.0 kJ/mol°

Your group must provide the engineering team with:

• A PowerPoint™ (or similar) presentation explaining the properties and reactions of various formulations of rocket propellant

• A recommendation on the best rocket propellant to use Process 1. Get together with your group based on instructions from your teacher. Each member of the

team should be assigned a different task, such as a slide on the different reactions. 2. In your group conduct research on the following:

(a) a categorization of each reaction according to fuel type (i.e., solid or liquid) (b) the quantity of energy released in each balanced reaction equation (the enthalpy

change of the reaction as written) (c) the quantity of energy released per gram of each fuel/reactant (or combination of

reactants) (d) the general design of engines for solid and liquid fuels

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3. When research is complete, meet with your group, consider each alternative from a variety of perspectives. Which of the fuels will be the most appropriate to recommend for use in the design team’s rocket?

4. Assemble your research into your PowerPoint presentation, which should include the following: • a title slide, including a purpose for the presentation, with the names of the group

members; • an introduction slide listing all the fuels that have been researched, and categorizing them

(as solid or liquid); • one slide briefly outlining the design of solid rocket motors including the pros and cons of

using solid fuels as rocket propellants; • one slide briefly outlining the design of liquid rocket motors including the pros and cons of

using liquid fuels as rocket propellants; • one slide which includes a table summarizing

o each reaction categorized according to fuel type (i.e., solid or liquid), o the quantity of energy released in each balanced reaction equation (the enthalpy

change of the reaction as written), and o the quantity of energy released per gram of each fuel/reactant (or combination of

reactants); • one or two slides recommending the best fuel to propel a rocket into orbit, which will carry

a large payload. The design may include multiple stages or multiple fuel types, as long as your team includes justifications from a number of perspectives (economical, environmental, etc.)

Your presentation need not include all your enthalpy calculations for your tables, but you should have this evidence available in case your client requests it.

Resources You might like to start your research at these sites and then find some of your own resources. The Roots of Rocketry This Web page gives a history of early rocketry, from ancient times through the 17th century. Brief History of Rockets NASA’s Web site for young people provides information on the development of rocketry technology. How Rockets Work About.com provides very good information on how fireworks work, including information on the chemicals used. Links at the bottom continue the topic with a discussion of solid- and liquid-fuelled rockets. How Rocket Engines Work HowStuffWorks is a great source of information on rockets, pictures of engine design, types of fuels, and information on the design of the Space Shuttle and its engines. Rocket Propulsion This Web site presents higher-level material showing various engine designs, and the mathematics and physics behind the thrust produced in rocket engines. Also check out the Rocket Propellants page on this site. Wikipedia: Rocket Propellant Always a good starting point for research, Wikipedia gives information on solid, liquid, and hybrid propellants. You might also like to search this encyclopedia for information on bipropellant rocket designs.

Unit 6 Chemical Energy

Nelson Chemistry Alberta 20–30 www.science.nelson.com © 2007 Thomson Nelson

Propellants This NASA page discusses the types of fuels used in different launch vehicles. Introduction to the Chemistry of Rocket Fuel Basic information on rocket fuels is presented here. What Are the Properties of a Good Rocket Fuel? Here you will find a pertinent discussion of how the heat capacity of the products, as well as the enthalpy of combustion of the reactants, affects the thrust of a rocket. Index of Propellants This site, which lists various rocket fuel mixtures alphabetically, includes their chemical properties and related economic data. Alternate Propellants for SSTO Launchers http://www.dunnspace.com/alternate_ssto_propellants.htm This information is adapted from a presentation given in 1996 by Dr. Bruce Dunn’s. The text discusses various rocket fuel mixtures, with information on their chemical properties⎯including molar enthalpies of formation. Enthalpy of Formation, Gibbs Function of Formation, and Absolute Entropy at 25°C, 1 atm While some of the information in this table is not relevant, the various fuel molar enthalpies of formation are. Evaluation Descriptor 4 3 2 1

• Presentation correctly categorized the reactants of the four listed reactions.

• Presentation correctly categorized most of the reactants of the four listed reactions.

• Presentation correctly categorized some of the reactants of the four listed reactions, with significant errors.

• Presentation failed to categorize the reactants of the four listed reactions.

• Several pros and cons of solid- and liquid-fuel rocket design were very clearly presented.

• Some pros and cons of solid- and liquid-fuel rocket design were clearly presented.

• Some pros and cons of solid- and liquid-fuel rocket design were presented.

• There is little or no discussion of pros and cons of solid- and liquid-fuel rocket design.

Content of audio-visual presentation

• Correct values were presented for the quantity of energy released in each balanced chemical reaction and per gram of fuel.

• Mostly correct values were presented for the quantity of energy released.

• Values presented for the quantity of energy released had some significant errors.

• Values were not presented for the quantity of energy released.

Unit 6 Chemical Energy

Nelson Chemistry Alberta 20–30 www.science.nelson.com © 2007 Thomson Nelson

• A reasoned recommendation is clearly stated.

• A recommendation is stated with some reasoning.

• A recommendation is loosely stated with little reasoning.

• No recommendation is stated.

• Presentation shows evidence of detailed research.

• Presentation shows evidence of adequate research.

• Presentation shows evidence of limited research.

• Presentation shows little evidence of research.

• All sources of information are correctly cited.

• Most sources of information are correctly cited.

• Some sources of information are cited, but not always correctly.

• Sources of information are not cited.

Overall quality of audio-visual presentation

• Presentation was very well organized, easy to follow, neat, appealing, and professional looking.

• Presentation was well organized, easy to follow, neat, appealing, and professional looking.

• Presentation was somewhat organized, easy to follow, neat, appealing, and professional looking.

• Presentation was not organized, easy to follow, neat, appealing, or professional looking.

Learning Outcomes Addressed 30–A1.4k write balanced equations for chemical reactions that include energy changes 30–A1.5k use and interpret ∆H notation to calculate energy changes in chemical reactions 30–A1.6k predict the enthalpy change for chemical equations using standard enthalpies of

formation 30–A1.8k use calorimetry data to determine the enthalpy changes in chemical reactions 30–A1.1sts explain that the goal of technology is to provide solutions to practical problems

• identify ways to use energy more efficiently 30–A1.2s conduct investigations into relationships among observable variables and use a

broad range of tools and techniques to gather and record data and information • select and integrate information from various print and electronic sources to

create multiple-linked documents on using alternative fuels 30–A1.3s analyze data and apply mathematical and conceptual models to develop and assess

possible solutions • compare energy changes associated with a variety of chemical reactions

through the analysis of data and energy diagrams • manipulate and present data through the selection of appropriate tools such as

scientific instrumentation, calculators, databases or spreadsheets 30–A1.4s work collaboratively in addressing problems and apply the skills and conventions of

science in communicating information and ideas and in assessing results • use appropriate International System of Units (SI) notation, fundamental and

derived units and significant digits • use advanced menu features within a word processor to accomplish a task and to

insert tables, graphs, text, and graphics In Summary This Web Quest will give you some insight into the fascinating area of rocketry. Rocket technology has been around for centuries. Modern space vehicles use sophisticated rocket technology and fuels for getting into orbit, maneuvering in orbit, and even generating electricity once in orbit. By completing this Web Quest you will have gained an appreciation of the history of rocketry, as well as the chemistry and design that goes into rocket motors.

Unit 6 Chemical Energy

Nelson Chemistry Alberta 20–30 www.science.nelson.com © 2007 Thomson Nelson