Investigating Burning Ethanol

Steps in Investigation 1.Initial prediction and explanation 2.Observations: Measurements of changes in mass and CO 2 3.Learning about 5 practices for describing chemical changes 4.Constructing an argument from evidence that combines claims, evidence, and reasoning

Steps in Investigation 1.Initial prediction and explanation 2.Observations: Measurements of changes in mass and CO 2 3.Learning about 5 practices for describing chemical changes 4.Constructing an argument from evidence that combines claims, evidence, and reasoning

In your own words…. Explain what happens when ethanol burns. Try to include in your explanation: – All the materials (solids, liquids, and gases) that are changed when ethanol burns. These are called reactants. – All the materials that result from ethanol burning. These are called products. – Changes in energy: what happens to the chemical energy in the ethanol. Predict changes that we will be able to measure

Ethanol burning Ethanol Before burning After burning Predictions for change in mass When ethanol burns, what happens to it and the things it needs to burn? Use the Process Tool to Show Your Prediction and Explanation

Steps in Investigation 1.Initial prediction and explanation 2.Observations: Measurements of changes in mass and CO 2 3.Learning about 5 practices for describing chemical changes 4.Constructing an argument from evidence that combines claims, evidence, and reasoning

A Question about BTB BTB (bromothymol blue) is an indicator that changes color when there is lots of carbon dioxide in the air. How could you figure out what color it changes?

Use the tables in your worksheet to record Mass of ethanol before and after for BTB experiment Color changes in BTB Mass of ethanol before and after for soda lime experiment Mass of soda lime before and after Other observations you made Possible problems with accurate measurement and how to make the measurements as accurate as possible.

Steps in Investigation 1.Initial prediction and explanation 2.Observations: Measurements of changes in mass and CO 2 3.Learning about 5 practices for describing chemical changes 4.Constructing an argument from evidence that combines claims, evidence, and reasoning

Five Practices for Finding Chemical Change in Life and Lifestyles QuestionsWhat to NoticePrinciple or Rule to Follow Have you identified all the materials that are changing (the reactants and products)? Organic materials: Foods, fuels, and living and dead organisms Gases: carbon dioxide, oxygen, and water vapor Conservation of matter: Chemical changes do not create or destroy matter; the amount of matter is the same in reactants and products Have you kept track of all the materials, even the gases? Can you show that no mass was lost or gained in the reaction? All states of matter: solids, liquids, and gases all have mass Not energy: heat, light, work, and chemical energy do not have mass Conservation of mass: Chemical changes do not change mass; the mass of the reactants equals the mass of the products Can you show that all the atoms present in the reactants are present in the products? Can you identify which materials are composed of organic molecules? Atoms: carbon (C), oxygen (O), hydrogen (H), other atoms such as nitrogen (N), and phosphorous (P) Organic molecules that have C-C or C-H bonds Inorganic molecules, including CO 2, H 2 O, and O 2 Conservation of atoms: Chemical changes rearrange atoms into new molecules, but they do not create or destroy atoms Can you show that energy was not gained or lost in the reaction? Chemical energy stored in the C-C and C- H bonds of organic molecules Other forms of energy, including light, work (motion), and heat Conservation of energy: Chemical changes transform energy without changing the total amount of energy, BUT some energy is always changed into heat that cannot be reused Can you identify where the event fits in large-scale systems, including ecosystems and human energy systems? Movement of carbon from pools of organic materials to inorganic materials and back again Flow of energy from sunlight to chemical energy to work and heat Matter cycles: carbon and other elements cycle between organic and inorganic materials Energy flows: sunlight is converted to chemical energy, then to work and heat

How did you use three practices to explain which materials will burn? The materials practice: Identifying organic and inorganic materials The subsytems practice: Identifying C-C and C-H bonds in molecules The energy practice Identifying materials with more chemical energy

Steps in Investigation 1.Initial prediction and explanation 2.Observations: Measurements of changes in mass and CO 2 3.Learning about 5 practices for describing chemical changes 4.Constructing an argument from evidence that combines claims, evidence, and reasoning

Claim, evidence, and reasoning Claim: What is your revised explanation of what happens when alcohol burns, including reactants, products, and energy transformations? Evidence: What observations and measurements support your claim? Reasoning: How does the evidence support your claim?

Ethanol burning Ethanol Before burning After burning Predictions for change in mass When ethanol burns, what happens to it and the things it needs to burn? Use the Process Tool to Show Your New Explanation

Does your explanation conserve matter? PracticeWhat to NoticePrinciple or Rule to Follow The Materials Practice: Identify the materials that are changing: Reactants and products Organic materials: Foods, fuels, and living and dead organisms Gases: carbon dioxide, oxygen, and water vapor Conservation of matter: Chemical changes do not create or destroy matter; the amount of matter is the same in reactants and products The Mass/gases Practice: Find the masses of reactants and products All states of matter: solids, liquids, and gases all have mass Not energy: heat, light, work, and chemical energy do not have mass Conservation of mass: Chemical changes do not change mass; the mass of the reactants equals the mass of the products The Subsystems Practice: Find out what is happening in subsystems at the microscopic scale (cells) and the atomic-molecular scale (atoms and molecules) Atoms: carbon (C), oxygen (O), hydrogen (H), other atoms such as nitrogen (N), and phosphorous (P) Organic molecules that have C-C or C-H bonds Inorganic molecules, including CO 2, H 2 O, and O 2 Conservation of atoms: Chemical changes rearrange atoms into new molecules, but they do not create or destroy atoms The Energy Practice: Find out how energy is transformed in the event Chemical energy stored in the C-C and C-H bonds of organic molecules Other forms of energy, including light, work (motion), and heat Conservation of energy: Chemical changes transform energy without changing the total amount of energy, BUT some energy is always changed into heat that cannot be reused The Large Scale Practice: Find out where the event fits in large-scale systems, including ecosystems and human energy systems Movement of carbon from pools of organic materials to inorganic materials and back again Flow of energy from sunlight to chemical energy to work and heat Matter cycles: carbon and other elements cycle between organic and inorganic materials Energy flows: sunlight is converted to chemical energy, then to work and heat

Does your explanation conserve mass? PracticeWhat to NoticePrinciple or Rule to Follow The Materials Practice: Identify the materials that are changing: Reactants and products Organic materials: Foods, fuels, and living and dead organisms Gases: carbon dioxide, oxygen, and water vapor Conservation of matter: Chemical changes do not create or destroy matter; the amount of matter is the same in reactants and products The Mass/gases Practice: Find the masses of reactants and products All states of matter: solids, liquids, and gases all have mass Not energy: heat, light, work, and chemical energy do not have mass Conservation of mass: Chemical changes do not change mass; the mass of the reactants equals the mass of the products The Subsystems Practice: Find out what is happening in subsystems at the microscopic scale (cells) and the atomic-molecular scale (atoms and molecules) Atoms: carbon (C), oxygen (O), hydrogen (H), other atoms such as nitrogen (N), and phosphorous (P) Organic molecules that have C-C or C-H bonds Inorganic molecules, including CO 2, H 2 O, and O 2 Conservation of atoms: Chemical changes rearrange atoms into new molecules, but they do not create or destroy atoms The Energy Practice: Find out how energy is transformed in the event Chemical energy stored in the C-C and C-H bonds of organic molecules Other forms of energy, including light, work (motion), and heat Conservation of energy: Chemical changes transform energy without changing the total amount of energy, BUT some energy is always changed into heat that cannot be reused The Large Scale Practice: Find out where the event fits in large-scale systems, including ecosystems and human energy systems Movement of carbon from pools of organic materials to inorganic materials and back again Flow of energy from sunlight to chemical energy to work and heat Matter cycles: carbon and other elements cycle between organic and inorganic materials Energy flows: sunlight is converted to chemical energy, then to work and heat

Does your explanation conserve atoms? PracticeWhat to NoticePrinciple or Rule to Follow The Materials Practice: Identify the materials that are changing: Reactants and products Organic materials: Foods, fuels, and living and dead organisms Gases: carbon dioxide, oxygen, and water vapor Conservation of matter: Chemical changes do not create or destroy matter; the amount of matter is the same in reactants and products The Mass/gases Practice: Find the masses of reactants and products All states of matter: solids, liquids, and gases all have mass Not energy: heat, light, work, and chemical energy do not have mass Conservation of mass: Chemical changes do not change mass; the mass of the reactants equals the mass of the products The Subsystems Practice: Find out what is happening in subsystems at the microscopic scale (cells) and the atomic-molecular scale (atoms and molecules) Atoms: carbon (C), oxygen (O), hydrogen (H), other atoms such as nitrogen (N), and phosphorous (P) Organic molecules that have C-C or C-H bonds Inorganic molecules, including CO 2, H 2 O, and O 2 Conservation of atoms: Chemical changes rearrange atoms into new molecules, but they do not create or destroy atoms The Energy Practice: Find out how energy is transformed in the event Chemical energy stored in the C-C and C-H bonds of organic molecules Other forms of energy, including light, work (motion), and heat Conservation of energy: Chemical changes transform energy without changing the total amount of energy, BUT some energy is always changed into heat that cannot be reused The Large Scale Practice: Find out where the event fits in large-scale systems, including ecosystems and human energy systems Movement of carbon from pools of organic materials to inorganic materials and back again Flow of energy from sunlight to chemical energy to work and heat Matter cycles: carbon and other elements cycle between organic and inorganic materials Energy flows: sunlight is converted to chemical energy, then to work and heat

Does your explanation conserve energy? PracticeWhat to NoticePrinciple or Rule to Follow The Materials Practice: Identify the materials that are changing: Reactants and products Organic materials: Foods, fuels, and living and dead organisms Gases: carbon dioxide, oxygen, and water vapor Conservation of matter: Chemical changes do not create or destroy matter; the amount of matter is the same in reactants and products The Mass/gases Practice: Find the masses of reactants and products All states of matter: solids, liquids, and gases all have mass Not energy: heat, light, work, and chemical energy do not have mass Conservation of mass: Chemical changes do not change mass; the mass of the reactants equals the mass of the products The Subsystems Practice: Find out what is happening in subsystems at the microscopic scale (cells) and the atomic-molecular scale (atoms and molecules) Atoms: carbon (C), oxygen (O), hydrogen (H), other atoms such as nitrogen (N), and phosphorous (P) Organic molecules that have C-C or C-H bonds Inorganic molecules, including CO 2, H 2 O, and O 2 Conservation of atoms: Chemical changes rearrange atoms into new molecules, but they do not create or destroy atoms The Energy Practice: Find out how energy is transformed in the event Chemical energy stored in the C-C and C-H bonds of organic molecules Other forms of energy, including light, work (motion), and heat Conservation of energy: Chemical changes transform energy without changing the total amount of energy, BUT some energy is always changed into heat that cannot be reused The Large Scale Practice: Find out where the event fits in large-scale systems, including ecosystems and human energy systems Movement of carbon from pools of organic materials to inorganic materials and back again Flow of energy from sunlight to chemical energy to work and heat Matter cycles: carbon and other elements cycle between organic and inorganic materials Energy flows: sunlight is converted to chemical energy, then to work and heat

Evidence of CO 2 in air from burning 4 minutes 8 minutes 10 minutes, with control