Chemical and Physical Changes in Matter

What is the main difference between a chemical change and a physical change?

• A chemical change creates a new substance, while a physical change does not.

• A physical change creates a new substance, while a chemical change does not.

• Both changes always create new substances.

• Neither change affects the substance at all.

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

• Rust forming on iron left outside

• Melting ice

• Cutting paper

• Mixing sand and salt

What is a common indicator of a chemical change?

• Change in color

• Change in size

• Change in shape

• Change in texture

Which of the following is NOT an indicator of a chemical change?

• Wadding a sheet of paper

• Odor change

• Formation of bubbles

• Temperature change

What happens at the molecular level during a chemical change?

• Bonds between atoms are broken or created

• Atoms are rearranged without breaking bonds

• Molecules are only moved closer together

• No change occurs at the molecular level

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

• Slicing an apple

• Burning wood

• Baking a cake

• Rusting iron

Why are chemical changes usually not easily reversed?

• They involve breaking and creating atomic bonds

• They only change the shape of the substance

• They do not involve energy changes

• They are always reversible

What is the chemical formula for water in both its liquid and solid states?

• H₂O

• CO₂

• O₂

• NaCl

Which of the following is a sign that a chemical reaction has occurred?

• Formation of a precipitate

• Cutting an apple

• Melting ice

• Mixing sand and water

What is an example of a physical change that can be reversed?

• Melting ice and then freezing it again

• Burning wood

• Baking cookies

• Rusting iron