4.4 Physical & Chemical Changes

Multiple Choice

Which of the following best describes a chemical change?

• A substance changes its appearance but not its composition.

• A substance changes into a different substance with new properties.

• A substance is mixed with another but can be separated easily.

• A substance is dissolved in water but remains the same chemically.

Open Ended

Why is it important to understand the difference between physical and chemical changes in substances?

Multiple Choice

Which of the following best describes a physical change as explained in the slides?

• A change in composition of a substance

• A change in properties without changing composition

• A chemical reaction forming new substances

• A process where atoms are rearranged into new molecules

Multiple Choice

Based on the diagrams and text, what is the main difference between the separation of mixtures and a chemical reaction?

• Separation of mixtures changes the chemical composition, while chemical reactions do not.

• Separation of mixtures only changes the form, not the nature, while chemical reactions create new substances.

• Both processes result in new substances being formed.

• Separation of mixtures involves breaking chemical bonds, while chemical reactions do not.

Fill in the Blanks

During a chemical change, bonds are

or formed.

Open Ended

Explain why the dissolution of salt in water can be considered both a physical and a chemical process.

Multiple Select

Which of the following processes involves only intermolecular forces being broken or formed?

• CH3OH(l) → CH3OH(g)

• 4Fe(s) + 3O2(g) → 2Fe2O3(s)

• 2Al2O3(s) → 4Al(s) + 3O2(g)

• CO2(s) → CO2(g)

Open Ended

What questions do you still have about physical and chemical changes, or would you like to know more about how substances change their properties?

Open Ended

How does the relationship between macroscopic characteristics and bond interactions differ in chemical processes compared to physical processes?