Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

5. Classification & Balancing of Chemical Reactions

Balancing Chemical Equations (Simplified)

GOB Chemistry

5. Classification & Balancing of Chemical Reactions

Balancing Chemical Equations (Simplified)

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2:39 minutes

Problem 23

Textbook Question

Why is it not possible to balance an equation by changing the subscript on a substance, say from H₂O to H₂O₂?

Verified step by step guidance

Understand the role of subscripts in a chemical formula: Subscripts indicate the number of atoms of each element in a molecule. Changing a subscript alters the identity of the compound, creating a completely different substance with different chemical properties.

Recognize the purpose of balancing a chemical equation: The goal is to ensure the law of conservation of mass is obeyed, meaning the number of atoms of each element is the same on both sides of the equation. This is achieved by adjusting coefficients, not subscripts.

Consider the implications of changing a subscript: For example, changing H₂O (water) to H₂O₂ (hydrogen peroxide) would mean you are no longer working with the same compound. This fundamentally changes the reaction and violates the principle of balancing the original equation.

Focus on adjusting coefficients: Coefficients are numbers placed in front of chemical formulas to indicate the quantity of molecules or moles. Adjusting coefficients allows you to balance the equation without altering the identity of the substances involved.

Apply this understanding to any chemical equation: Always preserve the subscripts as they define the chemical identity of the substances. Use coefficients to balance the equation while maintaining the integrity of the compounds.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Chemical Formula

A chemical formula represents the composition of a substance, indicating the types and numbers of atoms present. For example, H₂O indicates two hydrogen atoms and one oxygen atom, while H₂O₂ indicates two hydrogen atoms and two oxygen atoms. Changing the subscripts alters the identity of the substance, leading to different chemical properties and reactions.

Law of Conservation of Mass

The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction. This principle requires that the number of atoms of each element must be the same on both sides of a chemical equation. Changing subscripts would violate this law, as it would change the number of atoms and thus the mass of the reactants and products.

Balancing Chemical Equations

Balancing chemical equations involves adjusting coefficients (the numbers in front of compounds) to ensure that the same number of each type of atom appears on both sides of the equation. This process maintains the integrity of the substances involved while adhering to the Law of Conservation of Mass. Changing subscripts instead of coefficients would misrepresent the actual substances and their quantities.