Give reasons for the following
Q13. Carbon dioxide is a compound while carbon is an element .(2 points)
Q14. Air is a mixture. (2 points)
Q15. Rusting of iron is a chemical change while magnetization of iron a physical change.
Q13. Carbon dioxide is a compound while carbon is an element .(2 points)
Q14. Air is a mixture. (2 points)
Q15. Rusting of iron is a chemical change while magnetization of iron a physical change.
Answers & Comments
Answer:
1. Carbon dioxide is a compound as it contains more than one element and is chemically bonded together. It can be broken down into simpler substances. Carbon is an element as it can not be broken down into simpler substances by any chemical reaction.
2. Air is a mixture as it contains several compounds which are not in fixed proportions (variable composition). The mixture can be separated by physical means.
3. Rusting of iron involves chemical reaction which is irreversible while magnetization doesn't involve any chemical reaction and can be demagnetized (reversible).