Physical vs Chemical Changes: Key Concepts and Examples

The video by Diwanshi on ScienceQ explains the differences between physical and chemical changes. Physical changes alter the external features of a substance without affecting its molecular structure, making them reversible. Examples include melting ice and cutting paper. Chemical changes, however, involve altering the molecular structure, resulting in new substances and are irreversible, such as baking a cake or burning wood. The video concludes with a comparison of these changes, highlighting their distinct properties and examples.

What is a key characteristic of a physical change?

• It always produces energy.

• It alters the chemical composition.

• It is usually irreversible.

• It changes the external appearance.

Which of the following is an example of a physical change?

• Burning wood

• Melting ice

• Cooking an egg

• Baking a cake

What happens to the molecular structure during a chemical change?

• It becomes more compact.

• It only changes shape.

• It rearranges to form new substances.

• It remains unchanged.

Which of the following is NOT a characteristic of chemical changes?

• They are irreversible.

• They involve energy changes.

• They only affect physical properties.

• They produce new substances.

Which process is an example of a chemical change?

• Mixing sand and salt

• Curdling milk

• Boiling water

• Tearing paper

How do physical changes differ from chemical changes in terms of energy?

• Chemical changes do not require energy.

• Physical changes do not produce energy.

• Chemical changes never involve energy.

• Physical changes always release energy.

What is a common result of a chemical change?

• The substance changes color.

• The substance remains the same.

• The substance becomes colder.

• The substance becomes larger.

Which statement is true about physical changes?

• They are permanent.

• They require a chemical reaction.

• They create new substances.

• They are generally reversible.

What is a key difference between physical and chemical changes?

• Physical changes are irreversible.

• Chemical changes do not alter physical properties.

• Physical changes do not involve new substances.

• Chemical changes are temporary.

Which of the following is a characteristic of chemical changes?

• They are fast to occur.

• They do not affect the chemical properties.

• They involve the formation of new bonds.

• They are easily reversible.