Understanding Physical and Chemical Changes

What is the main focus of the lesson on physical and chemical changes?

• To memorize chemical formulas

• To understand the difference between physical and chemical changes

• To learn about the history of chemistry

• To study the periodic table

When water boils and turns into steam, what type of change is occurring?

• Chemical change

• Physical change

• Nuclear change

• Biological change

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

• Cooking an egg

• Melting ice

• Rusting iron

• Burning wood

What happens to the substance during a physical change?

• It disappears completely

• It becomes a new substance

• It remains the same substance

• It changes its chemical properties

Which process is NOT a physical change?

• Burning a candle

• Dissolving sugar in water

• Crushing a can

• Freezing water into ice

What question should you ask to determine if a change is physical?

• Is it heavier?

• Does it smell different?

• Has it changed color?

• Is it still the same substance?

What is an example of a change of state that is a physical change?

• Water boiling

• Iron rusting

• Wood burning

• Milk souring

What is the result of dissolving salt in water?

• The salt disappears completely

• A physical change occurs

• A new substance is formed

• A chemical change occurs

How can you tell if a change is chemical?

• The substance changes shape

• The substance changes color

• The substance melts

• A new substance is formed

What is the key indicator of a physical change?

• Emission of light

• Change in physical properties

• Change in temperature

• Formation of a new substance