ACS: Inquiry in Action - Substances Can Mix and React to Form New Substances (Lesson 3.5): Different Substances React Differently
Students combine citric acid with calcium chloride and citric acid with baking soda to investigate the question: What are the similarities and differences between the two reactions? and Do substances react in a characteristic way?
Objective
Students will be able to explain that if they mix baking soda with two different substances in separate containers and observe different signs of chemical reactions, it must be because the two substances are different. The substances must be made from different molecules, which react differently with baking soda.
Key Concepts
- Because substances are made up of different atoms and molecules, they react in characteristic ways.
- Production of a gas, color changes, a change in temperature, and the formation of a precipitate are all evidence of a chemical reaction.
NGSS Alignment
- NGSS 5-PS1-4: Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
Summary
In working with chemical reactions, students have seen a gas produced, a precipitate formed, and changes in color. They have also seen that substances interact in characteristic ways and that these reactions can help identify a substance. In this activity:
- Students conduct a reaction with citric acid and baking soda in a universal indicator solution. The resulting chemical reaction produces a gas, causes a color change with an indicator, and results in a decrease in temperature.
- Students then carry out a second reaction with calcium chloride and baking soda in the universal indicator solution. In this example, students observe the production of both a gas and a solid, a color change with the indicator, and a slight increase in temperature.
- Students reason that since baking soda was reacted with two different substances, it makes sense that the reactions they observed were different. Finally, students conclude that different substances have characteristic chemical reactions and that these reactions can be used to identify a substance.
Evaluation
Download the student activity sheet (PDF) and distribute one per student when specified in the activity. The activity sheet will serve as the Evaluate component of the 5-E lesson plan.
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Students squeeze a flexible plastic bottle filled with air and another filled with water to investigate the questions: Is an “empty” bottle really empty? and Can you force the molecules of a gas or a liquid to be closer together?
Students compare the dissolving of salt and sugar and then conduct a dissolving test on unknown substances marked A, B, and C to investigate the question: Can substances be identified by how well they dissolve in water?
Students help design a test using baking soda, corn starch, and cream of tartar to investigate the question: Which two of the three ingredients in baking powder react to make it bubble when water is added?
Students add laundry detergent powder (a base) and cream of tartar (an acid) to a red cabbage indicator to investigate the question: What can the color of an indicator tell you about the substances added to it?
Students combine an Ivory Soap solution with an Epsom salt solution to produce a solid “soap scum” to investigate the questions: What happens when you mix soap with hard water? and Is soap scum different from soap?
Students design and conduct a test using baking soda and baking powder with vinegar to investigate the question: Will baking soda or baking powder produce more gas when vinegar is added?
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Students combine citric acid with calcium chloride and citric acid with baking soda to investigate the question: What are the similarities and differences between the two reactions? and Do substances react in a characteristic way?
Objective
Students will be able to explain that if they mix baking soda with two different substances in separate containers and observe different signs of chemical reactions, it must be because the two substances are different. The substances must be made from different molecules, which react differently with baking soda.
Key Concepts
- Because substances are made up of different atoms and molecules, they react in characteristic ways.
- Production of a gas, color changes, a change in temperature, and the formation of a precipitate are all evidence of a chemical reaction.
NGSS Alignment
- NGSS 5-PS1-4: Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
Summary
In working with chemical reactions, students have seen a gas produced, a precipitate formed, and changes in color. They have also seen that substances interact in characteristic ways and that these reactions can help identify a substance. In this activity:
- Students conduct a reaction with citric acid and baking soda in a universal indicator solution. The resulting chemical reaction produces a gas, causes a color change with an indicator, and results in a decrease in temperature.
- Students then carry out a second reaction with calcium chloride and baking soda in the universal indicator solution. In this example, students observe the production of both a gas and a solid, a color change with the indicator, and a slight increase in temperature.
- Students reason that since baking soda was reacted with two different substances, it makes sense that the reactions they observed were different. Finally, students conclude that different substances have characteristic chemical reactions and that these reactions can be used to identify a substance.
Evaluation
Download the student activity sheet (PDF) and distribute one per student when specified in the activity. The activity sheet will serve as the Evaluate component of the 5-E lesson plan.
Back to Fifth Grade Lessons
Guided instructions, lesson plans, classroom activities, video demonstrations, and activity books.
Students squeeze a flexible plastic bottle filled with air and another filled with water to investigate the questions: Is an “empty” bottle really empty? and Can you force the molecules of a gas or a liquid to be closer together?
Students compare the dissolving of salt and sugar and then conduct a dissolving test on unknown substances marked A, B, and C to investigate the question: Can substances be identified by how well they dissolve in water?
Students help design a test using baking soda, corn starch, and cream of tartar to investigate the question: Which two of the three ingredients in baking powder react to make it bubble when water is added?
Students add laundry detergent powder (a base) and cream of tartar (an acid) to a red cabbage indicator to investigate the question: What can the color of an indicator tell you about the substances added to it?
Students combine an Ivory Soap solution with an Epsom salt solution to produce a solid “soap scum” to investigate the questions: What happens when you mix soap with hard water? and Is soap scum different from soap?
Students design and conduct a test using baking soda and baking powder with vinegar to investigate the question: Will baking soda or baking powder produce more gas when vinegar is added?
What are you looking for?
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Type of Resource
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