Read the following case and answer the questions given below:
During a science practical session, Ms. Anita asked her students to observe different activities taking place around them and identify whether each activity was a physical or a chemical change.
Rahul folded a sheet of paper into the shape of an airplane. Priya burnt another sheet of paper using a matchstick. Karan inflated a balloon by blowing air into it. Meanwhile, Meera mixed vinegar with baking soda in a beaker and observed vigorous fizzing with bubbles being produced.
After observing all four activities, the teacher asked the students to compare the changes and explain the scientific reason behind each one.
Rahul folded a sheet of paper into the shape of an airplane. Priya burnt another sheet of paper using a matchstick. Karan inflated a balloon by blowing air into it. Meanwhile, Meera mixed vinegar with baking soda in a beaker and observed vigorous fizzing with bubbles being produced.
After observing all four activities, the teacher asked the students to compare the changes and explain the scientific reason behind each one.
1. Classify the activities of folding a sheet of paper and burning a sheet of paper as physical or chemical changes. Give a reason for each.
Folding a sheet of paper is a because and . Burning a sheet of paper is a because , and the change is .
2. Why is inflating a balloon considered a physical change, whereas mixing vinegar with baking soda is considered a chemical change?
Inflating a balloon is a because only the , and . Mixing vinegar with baking soda is a because and other new substances are formed, which is indicated by .
3. What observations help you identify that burning paper and mixing vinegar with baking soda are chemical changes?
Both activities are because . In burning paper, are produced, while in mixing vinegar with baking soda, is released as . These observations indicate that a .