# Physical and Chemical changes A chemical change occurs

• Slides: 9

Physical and Chemical changes

A chemical change occurs when the composition of matter changes, such as when a piece of paper burns to ashes. A physical change alters the physical properties but there is no change in the matterâ€™s composition.

Your team has 2 minutes to brainstorm as many physical changes that could possibly occur in your matter sample. Choose 1 person in your group to record your responses on the chart paper.

Record the weight of a sheet of cardboard. Tear or cut the cardboard into small pieces. Again, record the weight. It the weight the same or different? How do you explain this?

Place 2 tablespoons of vinegar into a 2 -liter bottle. Pour 1 tablespoon of baking soda into a balloon. Carefully attach the balloon to the top of the bottle. Record the mass of the bottle, baking soda, balloon, and vinegar. Mix the vinegar into the baking soda by lifting the balloon and allowing the baking soda to pour into the bottle. Record the weight of the items. Is the weight the same or different? How would you explain this?

Remove the balloon. Put the balloon and bottle on the scale and weigh the items. Is the weight the same or different? How would you explain this? How does this experiment compare with the cardboard experiment? What is similar and what is different?

Why did the weight of the paper remain the same after it was torn apart? Why was the weight of the vinegar, balloon, baking soda and bottle the same before the reaction as it was after? Why did the weight change when the balloon was removed?

1. 2. 3. 10 g of water is frozen. What will its weight be when it melts. Explain your answer. 5 g of salt is dissolved in 10 g of water. What will the weight of the salt water be? Explain your answer? You weighed a telephone, then took the phone apart. Predict the weight of the disassembled phone. CHOOSE 1 to answer on a sheet of paper.

A chemical change occurs when the composition of matter changes, such as when a piece of paper burns to ashes. A physical change alters the physical properties but there is no change in the matterâ€™s composition. Matter is neither created nor destroyed even though it may undergo changes.