Chemical and Physical Changes in Matter

The video discusses changes in matter, focusing on the law of conservation of matter and energy. It explains physical changes, where the appearance or state of matter changes without forming new substances, and chemical changes, where new substances are formed through molecular bond alterations. Examples of both types of changes are provided, and guidance is given on identifying whether a change is physical or chemical.

What does the law of conservation of matter and energy state?

• Matter and energy can be created and destroyed.

• The amount of matter and energy in the universe is constant.

• Energy can be created but not destroyed.

• Matter can be destroyed but not created.

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

• Burning wood

• Baking a cake

• Freezing water

• Rusting iron

What happens to water molecules when water is frozen?

• They change into a different substance.

• They disappear.

• They remain water molecules but change state.

• They become gas molecules.

Which process is NOT a physical change?

• Breaking a glass

• Burning a candle

• Mixing sand and water

• Boiling water

What defines a chemical change?

• The separation of a mixture.

• The formation of a new substance.

• A change in the state of a substance.

• A change in the appearance of a substance.

Which of the following is a chemical change?

• Melting ice

• Chopping wood

• Mixing marbles

• Burning paper

What happens during the rusting of iron?

• Iron changes state from solid to liquid.

• Iron is mixed with water but remains unchanged.

• Iron combines with oxygen to form a new substance.

• Iron is physically broken into smaller pieces.

Which reaction occurs when baking soda and vinegar are mixed?

• A simple mixture that can be easily separated.

• A change in state from solid to liquid.

• A chemical change releasing gases and forming new substances.

• A physical change with no new substances formed.

Why is baking a cake considered a chemical change?

• Because it forms a new substance that cannot be reversed.

• Because it involves mixing ingredients.

• Because it involves heating the ingredients.

• Because it changes the appearance of the ingredients.

What indicates a chemical change in a banana left on the counter?

• The banana changes shape.

• The banana changes color due to chemical reactions.

• The banana becomes colder.

• The banana mixes with other fruits.