LESSON INFOGRAPHIC · إنفوجرافيك الدرس

Chemical Reactions التفاعلات الكيميائية

Three connected parts, five visual pages · ثلاثة أجزاء مترابطة في خمس صفحات مرئية

Based on Inspire Science Biology, Lesson 2, textbook pp. 137–143. Symbols and example equations follow the textbook. الأمثلة والصيغ الكيميائية وفق الكتاب.

PART 1 OF 3 · الجزء الأول

Chemical Reactions & Equations التفاعلات الكيميائية والمعادلات

Chemical Reactions

When substances change and atoms rearrange

Page 1

Subject: Biology Stage: 9 adv Prepared by Mr. Mahmoud Fouad

1What happens in a reaction?

A chemical reaction rearranges atoms into new substances. Bonds in the reactants break, and new bonds form in the products.

Reactants
Starting substances→Products
New substances

The number of each kind of atom stays the same.

2Chemical or physical change?

Chemical change

A new substance forms.

Iron rusts

Physical change

The substance keeps its composition.

Water boils

Clues may include a change in temperature, light, or formation of a gas, liquid, or solid. Check whether the composition changed.

3Read a chemical equation

Reactants
left side→Products
right side

The arrow means yields or produces. Chemical formulas tell us which elements and how many atoms are in each substance.

H₂ + O₂ → H₂O Water formation · before balancing

4Before you balance

A subscript is part of a chemical formula: the ₂ in O₂ means two oxygen atoms in one molecule. A coefficient is written before a formula: 2H₂O means two water molecules.

Change coefficients only; never change the subscripts in the formulas.