Grade 8 students explore how chemical reactions are essential to both living organisms and modern technology in this lesson from Physical Science, Chapter 7. Students learn how cellular respiration uses enzymes as catalysts to break down glucose through combustion, producing carbon dioxide, water, and usable energy, and how this process compares to photosynthesis. The lesson also examines industrial applications, including how catalysts manage combustion reactions in car engines and the production of byproducts like carbon monoxide and nitric oxide.
Section 1
📘 Life and industry depend on chemical reactions
Explore how chemical reactions are fundamental to both life and industry. You'll see how processes like respiration and modern manufacturing all rely on chemistry.
Section 2
Living Cells Release Energy from Glucose
Living things get energy by breaking down glucose through respiration. This process, the reverse of photosynthesis, uses oxygen to 'burn' sugar, releasing vital energy for life functions. The reaction is C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy. Biological catalysts called enzymes speed up this essential reaction in our cells.
Section 3
Car Engines Produce Harmful Pollutants
When a car burns gasoline, the reaction is often incomplete. This inefficiency creates harmful waste gases like poisonous carbon monoxide (CO) and nitric oxide (NO). These pollutants are released from the exhaust and can mix with water in the air to form smog and acid rain, posing a threat to our environment.
Section 4
Catalytic Converters Clean Up Car Exhaust
To solve the problem of car pollution, engineers designed the catalytic converter. This device uses metal catalysts, like platinum, to speed up reactions that neutralize harmful exhaust gases. It converts dangerous carbon monoxide and nitric oxide into safer atmospheric gases like nitrogen (N₂), carbon dioxide (CO₂), and water.
Section 5
Industries Create Pure Silicon for Electronics
Modern electronics depend on the semiconductor silicon. To produce it, industries use a chemical reaction that heats quartz (SiO₂) with carbon at high temperatures. The reaction, SiO₂ + 2C → Si + 2CO, creates silicon that is then purified to an extreme degree. This ultra-pure silicon forms the foundation for microchips.
Section 6
Manufacturers Use Light to Etch Circuits on Chips
Creating a microchip's tiny circuits involves a chemical process using light. A silicon wafer is coated with photoresist, a light-sensitive chemical. When ultraviolet light shines through a stencil, it triggers a reaction, hardening the photoresist into a circuit pattern. The unexposed material is then washed away, leaving the microscopic electrical pathways.
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Section 1
📘 Life and industry depend on chemical reactions
Explore how chemical reactions are fundamental to both life and industry. You'll see how processes like respiration and modern manufacturing all rely on chemistry.
Section 2
Living Cells Release Energy from Glucose
Living things get energy by breaking down glucose through respiration. This process, the reverse of photosynthesis, uses oxygen to 'burn' sugar, releasing vital energy for life functions. The reaction is C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy. Biological catalysts called enzymes speed up this essential reaction in our cells.
Section 3
Car Engines Produce Harmful Pollutants
When a car burns gasoline, the reaction is often incomplete. This inefficiency creates harmful waste gases like poisonous carbon monoxide (CO) and nitric oxide (NO). These pollutants are released from the exhaust and can mix with water in the air to form smog and acid rain, posing a threat to our environment.
Section 4
Catalytic Converters Clean Up Car Exhaust
To solve the problem of car pollution, engineers designed the catalytic converter. This device uses metal catalysts, like platinum, to speed up reactions that neutralize harmful exhaust gases. It converts dangerous carbon monoxide and nitric oxide into safer atmospheric gases like nitrogen (N₂), carbon dioxide (CO₂), and water.
Section 5
Industries Create Pure Silicon for Electronics
Modern electronics depend on the semiconductor silicon. To produce it, industries use a chemical reaction that heats quartz (SiO₂) with carbon at high temperatures. The reaction, SiO₂ + 2C → Si + 2CO, creates silicon that is then purified to an extreme degree. This ultra-pure silicon forms the foundation for microchips.
Section 6
Manufacturers Use Light to Etch Circuits on Chips
Creating a microchip's tiny circuits involves a chemical process using light. A silicon wafer is coated with photoresist, a light-sensitive chemical. When ultraviolet light shines through a stencil, it triggers a reaction, hardening the photoresist into a circuit pattern. The unexposed material is then washed away, leaving the microscopic electrical pathways.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter