Chemical and Physical changes

Front

What is a chemical change?

Back

A chemical change is a process where substances combine or break apart to form new substances with different properties. Examples include baking a cake, rusting iron, and burning wood.

Front

What is a physical change?

Back

A physical change is a process that alters the form or appearance of a substance but does not change its chemical composition. Examples include melting ice, breaking glass, and dissolving sugar in water.

Front

What happens to the mass when substances are combined?

Back

The total mass of the mixture is equal to the sum of the masses of the individual substances. For example, combining 100 grams of sand, 200 grams of soil, and 200 grams of pebbles results in a total mass of 500 grams.

Front

Give an example of a chemical change.

Back

Baking a cake is an example of a chemical change because the ingredients undergo a chemical reaction to form a new substance.

Front

Give an example of a physical change.

Back

Melting ice is an example of a physical change because the ice changes from solid to liquid but remains water.

Front

What is the weight of a typical pencil?

Back

A typical pencil weighs about 5 grams.

Front

Is shattering a glass bottle a chemical or physical change?

Back

Shattering a glass bottle is a physical change because the glass is broken into pieces but its chemical composition remains the same.

Front

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

Back

A chemical change results in the formation of new substances, while a physical change only alters the appearance or state of a substance without changing its chemical identity.

Front

What are some signs of a chemical change?

Back

Signs of a chemical change include color change, temperature change, gas production, and the formation of a precipitate.

Front

What are some signs of a physical change?

Back

Signs of a physical change include changes in state (solid, liquid, gas), shape, and size without altering the substance's chemical identity.