Chemical and Physical Changes

What is a chemical reaction?

• A process that leads to the transformation of weather patterns

• A process that leads to the transformation of one set of chemical substances to another

• A process that leads to the transformation of physical properties

• A process that leads to the transformation of energy

Give an example of a physical change.

• Melting of ice

• Burning of wood

• Boiling of water

• Rusting of iron

What are some signs of a chemical change?

• Change in temperature

• Color change, production of gas, formation of a precipitate, and release of heat or light

• Change in state of matter

• Change in shape or size

Is burning wood a chemical or physical change? Why?

• Spiritual change

• Emotional change

• Physical change

• Chemical change

What happens to the composition of a substance during a physical change?

• It disappears completely

• It becomes radioactive

• It turns into a different element

• It remains the same

Explain the difference between a chemical change and a physical change.

• A chemical change involves the change in color of a substance, while a physical change only alters the form or appearance of a substance without changing its chemical composition

• A chemical change only alters the form or appearance of a substance without changing its chemical composition, while a physical change involves the formation of new substances with different properties

• A chemical change involves the change in state of a substance, while a physical change only alters the form or appearance of a substance without changing its chemical composition

• A chemical change involves the formation of new substances with different properties, while a physical change only alters the form or appearance of a substance without changing its chemical composition.

What are some examples of evidence of a chemical change?

• Change in texture

• Change in state of matter

• Formation of a precipitate, color change, gas production, and temperature change

• Change in shape

How can you tell if a chemical change has occurred?

• By tasting the substance

• By smelling the substance

• By observing the change in temperature

• By observing the formation of a new substance, change in color, production of gas, or release of energy.

What are some examples of physical changes?

• Baking a cake, mixing salt and water, burning wood

• Melting ice, boiling water, cutting paper

• Freezing water, dissolving sugar, fermenting grapes

• Digesting food, photosynthesis, rusting of iron

Why is it important to distinguish between chemical and physical changes?

• To understand the nature of the changes and their impact on the substances.

• Because it doesn't really matter, they are basically the same

• To confuse students and make the topic more difficult

• To waste time and make the learning process more tedious