Chemical reactions and equations Full chapter in animation | CBSE Class 10 | NCERT Science ch -1

Summary

This video explores various chemical reactions and equations in everyday life, explaining how substances change chemically. It covers examples like milk curdling, rusting iron, and the digestion process, all demonstrating chemical changes. The video dives into lab-based chemical reactions, balancing chemical equations, and types of reactions like combination, decomposition, displacement, and redox reactions. Additionally, it highlights real-life occurrences like corrosion and rancidity. The video provides a detailed yet accessible explanation of these fundamental chemical concepts, ensuring viewers understand how they manifest in daily experiences.

Takeaways

• 😀 Chemical changes occur when substances undergo transformations that change their chemical nature, such as milk souring or iron rusting.
• 😀 Chemical reactions involve changes in state, color, gas evolution, temperature change, and a change in the chemical nature of substances.
• 😀 A chemical equation can be written as a word equation, such as 'magnesium + oxygen → magnesium oxide', with reactants on the left and products on the right.
• 😀 Skeletal equations are unbalanced, and balancing them ensures the law of conservation of mass is satisfied by ensuring atoms are conserved.
• 😀 Balancing a chemical equation involves adjusting the number of atoms of each element on both sides, typically using the hit-and-trial method.
• 😀 The physical states of reactants and products, such as solid (S), liquid (L), gas (G), and aqueous (AQ), are indicated in chemical equations to provide more information.
• 😀 Combination reactions involve two or more reactants combining to form a single product, e.g., the formation of water from hydrogen and oxygen.
• 😀 Exothermic reactions release heat, such as the burning of coal or the respiration of glucose.
• 😀 Decomposition reactions involve a single compound breaking down into two or more simpler substances, such as calcium carbonate decomposing into calcium oxide and carbon dioxide.
• 😀 Displacement reactions involve one element replacing another in a compound, like iron displacing copper from copper sulfate solution.
• 😀 Oxidation involves the gain of oxygen, while reduction involves the loss of oxygen; reactions where both occur are called redox reactions.
• 😀 Corrosion, such as rusting of iron or tarnishing of silver, is a result of oxidation, while rancidity occurs when fats are oxidized and change in smell and taste.

Q & A

What is a chemical change?

A chemical change is a process where the chemical nature of the initial substances is altered. Examples include milk turning sour, iron rusting, or food being digested and converted into useful nutrients.

What happens during a chemical reaction?

During a chemical reaction, reactants undergo changes such as a change in state, color, temperature, or the evolution of gas, leading to the formation of new products with a different chemical composition.

What is the difference between a word equation and a chemical equation?

A word equation describes a chemical reaction using the names of the substances involved, whereas a chemical equation uses chemical formulas to represent the reactants and products.

What is the law of conservation of mass?

The law of conservation of mass states that in a closed system, the mass of the reactants must equal the mass of the products. Atoms are neither created nor destroyed in a chemical reaction; they are simply rearranged.

How do you balance a chemical equation?

To balance a chemical equation, adjust the coefficients of reactants and products so that the number of atoms of each element is the same on both sides of the equation. This is often done using the 'hit and trial' method.

What are combination reactions?

Combination reactions are chemical reactions where two or more reactants combine to form a single product. An example is the formation of water from hydrogen and oxygen.

What are exothermic reactions?

Exothermic reactions are chemical reactions that release energy in the form of heat. For example, burning natural gas or cellular respiration in living organisms.

What is a decomposition reaction?

A decomposition reaction is a type of chemical reaction where a single compound breaks down into two or more simpler substances. For instance, heating calcium carbonate leads to calcium oxide and carbon dioxide.

What are displacement reactions?

Displacement reactions involve one element displacing another in a compound. For example, iron reacts with copper sulfate to form iron sulfate and copper.

What is an oxidation-reduction (redox) reaction?

A redox reaction is a type of reaction where one substance gains oxygen (oxidized) and another loses oxygen (reduced). An example is the reaction between copper oxide and hydrogen gas, where copper is reduced and hydrogen is oxidized.