Chemical Reactions

Chemical reactions

100

What is the definition of a chemical reaction?

A process in which one or more substances are converted into new substances with different properties.

200

What are reactants and products in a chemical reaction?

Reactants are the starting materials that undergo the chemical change. Products are the new substances formed as a result of the reaction.

300

Write the chemical equation for the reaction between hydrogen and oxygen to form water.

2H₂ + O₂ → 2H₂O

400

What is the Law of Conservation of Matter?

Matter cannot be created or destroyed in a chemical reaction; the number of atoms of each element remains constant.

500

Explain the difference between a physical change and a chemical reaction.

A physical change does not alter the chemical composition of the substance (e.g., melting ice), while a chemical reaction produces new substances with different properties (e.g., burning wood).

Balancing Equations

100

Na + Cl₂ → NaCl

2Na + Cl₂ → 2NaCl

200

C₄H₁₀ + O₂ → CO₂ + H₂O

2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O

300

C₆H₁₂O₆ + O₂ → CO₂ + H₂O

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

400

Explain how to balance a combustion reaction

In a combustion reaction, balance carbon first (CO₂), then hydrogen (H₂O), and finally oxygen (O₂) by adjusting the coefficients. Ensure that the same number of each atom appears on both sides of the equation.

500

C₈H₁₈ + O₂ → CO₂ + H₂O

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2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O

Reaction Types

100

What type of reaction is: 2H₂ + O₂ → 2H₂O?

Synthesis reaction

200

What type of reaction is: AB → A + B

Decomposition reaction

300

What type of reaction is: CH₄ + 2O₂ → CO₂ + 2H₂O?

Combustion reaction

400

What type of reaction is: 2NaHCO_{3 ----------->} Na₂CO₃ + CO₂ + H₂O

Decomposition reaction (One substance breaks down into simpler substances)

500

2CH₃OH(g) + 3O₂(g) → 2CO₂(g) + 4H₂O(g)

Combustion reaction (Methanol also known as wood alcohol burns in the presence of oxygen).