Chemical Reactions — Reading Comprehension

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MS-PS1-2
MS-PS1-5

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This engaging middle school science passage introduces students to the fundamentals of chemical reactions, focusing on the transformation of reactants to products and the conservation of matter through atom rearrangement. Aligned to NGSS standards MS-PS1-2 and MS-PS1-5, the passage uses real-world examples such as combustion, rusting, baking, and photosynthesis to illustrate energy changes and cause-and-effect relationships. Students will gain a deeper understanding of how chemical processes drive everyday phenomena, and how energy is involved in both releasing and absorbing reactions. The resource includes a glossary, differentiated reading versions, Spanish translations, comprehension questions, writing prompts, and graphic organizers to support diverse learners. Audio integration is available for accessibility and enhanced learning. This comprehensive package is ideal for classrooms seeking to build scientific literacy and critical thinking around core chemistry concepts.

CONTENT PREVIEW

chemical-reaction-1 — Illustration showing atoms rearranging during a chemical reaction

Chemical reactions are central to life on Earth and technology in our world. When iron is left outside, it forms rust. In a kitchen, baking a cake changes flour and sugar into something new. These changes are not just physical; they are chemical. In every chemical reaction, substances called reactants are transformed into different substances known as products. Understanding how and why these changes occur helps us explain everything from how plants grow to how fuels burn.

How Chemical Reactions Work
At the atomic level, chemical reactions happen when atoms in the reactants rearrange to form new combinations. The number and type of atoms are the same before and after the reaction, which is known as the conservation of mass. During a reaction, chemical bonds between atoms break and new bonds form. These changes can either release energy (exothermic reactions) or absorb energy (endothermic reactions). For example, combustion—a reaction between a fuel and oxygen—releases heat and light. In contrast, photosynthesis in plants absorbs energy from sunlight to create sugar from carbon dioxide and water.

Examples and Applications of Chemical Reactions
Combustion is a common example: gasoline in a car engine reacts with oxygen, producing carbon dioxide, water, and energy that powers the vehicle. Rusting is another chemical reaction, where iron and oxygen react slowly in the presence of water to form iron oxide (rust). Baking a cake involves many reactions, such as the release of carbon dioxide gas from baking powder, causing the cake to rise. Photosynthesis is an essential reaction for life on Earth, as plants convert sunlight, carbon dioxide, and water into oxygen and glucose. Research shows that photosynthesis captures over 130 terawatts of solar energy globally each year, supporting nearly all life on Earth.

Interconnectedness and Broader Impacts
Chemical reactions are not isolated events—they connect to larger cycles and systems. The oxygen produced in photosynthesis is used in respiration by animals and humans, completing the carbon-oxygen cycle. Industrial chemical reactions produce materials for technology, medicine, and daily needs, but can also create pollution if not managed responsibly. Understanding these processes allows us to innovate new materials, develop cleaner energy sources, and address environmental challenges. The study of chemical reactions illustrates the principle that matter is conserved, but transformed in ways that shape our world.

In summary, chemical reactions involve the rearrangement of atoms, transforming reactants into products, and are driven by energy changes. These reactions are vital for life, industry, and the environment, demonstrating the interconnectedness of scientific systems and principles.

Interesting Fact: The chemical reaction in photosynthesis is so efficient that it provides the oxygen we breathe and the food base for almost every ecosystem on Earth!

What is the main purpose of a chemical reaction?

To transform reactants into products by rearranging atoms.To mix substances without changing them.To create physical changes only.To remove atoms from the environment.

Which statement best describes the conservation of mass?

Atoms are created and destroyed during reactions.The total number of atoms stays the same before and after the reaction.Reactions only happen in living things.Energy is not involved in chemical reactions.

What are the starting substances in a chemical reaction called?

ProductsReactantsBondsCycles

In the passage, what is an example of an exothermic reaction?

PhotosynthesisRustingCombustionMixing water with sugar

What does 'products' mean as used in the passage?

The new substances formed from a chemical reaction.The starting materials of a reaction.The energy released during a reaction.The process of mixing substances.

What does 'chemical bonds' refer to in the passage?

The connections between atoms that break and form during reactions.The air that plants use.A type of physical change.The energy stored in plants.

Why is photosynthesis important for life on Earth?

It provides oxygen and food for most living things.It creates pollution.It destroys energy.It only helps plants.

Which of the following is NOT an example of a chemical reaction discussed in the passage?

CombustionMelting iceRustingBaking a cake

True or False: All chemical reactions release energy as heat and light.

TrueFalse

True or False: In chemical reactions, the atoms are rearranged but not lost.

TrueFalse