Lesson 7 of 12
🔥 Chemical Reactions
What You'll Learn
- reactants vs products
- law of conservation of mass
- types: synthesis/decomposition/combustion
- pH scale acids & bases
Key Concepts
Chemical reactions rearrange atoms to form new substances. Reactants go in; products come out. The total mass of reactants always equals the total mass of products (Law of Conservation of Mass).
Types of reactions: synthesis (A+B→AB), decomposition (AB→A+B), combustion (fuel+O₂→CO₂+H₂O+energy), single replacement, double replacement.
The pH scale measures acidity (0–14). pH<7 = acid (lemon juice pH 2). pH=7 = neutral (pure water). pH>7 = base (baking soda pH 9). Indicators like litmus paper change color to show pH.
🔬 Virtual Lab
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Quick Check
The law of conservation of mass states that:
A substance with a pH of 3 is: