Chapter U1.8, Problem 1TAI

Interpretation Introduction

Interpretation:

The change in elements in a chemical change needs to be explained.

Concept introduction:

Sometimes matter is changed into new physical forms and sometimes it is changed into a new substance. Some changes are temporary while some changes are permanent. When a substance is changed or converted into another substance, a chemical change occurs. This chemical change is called chemical reaction.

Answer to Problem 1TAI

During a chemical change, the elements are neither created nor destroyed. They are always present in the new compounds that are formed. There is a conservation of mass of elements during a chemical change.

Explanation of Solution

Given information:

Elements undergo chemical changes.

Change is part of nature. Matter can be changed into new substances. Such changes which produce an entirely different substance are called chemical changes.

The copper cycle experiment shows that many different products are formed as copper is treated with different acids, a base and a metal. The cycle is a full circle as it brings back the element copper with which the cycle starts. After several steps, copper is obtained again. Whatever treatment is done on copper, there is copper always present in some form in the new products. It is neither created nor destroyed by chemical changes.

Hence, one can say that during chemical changes the elements are neither created nor destroyed. They are always present in the new compounds that are formed. There is a conservation of mass of elements in a chemical change.

Conclusion

During chemical changes the elements are neither created nor destroyed. They are always present in the new compounds that are formed. There is a conservation of mass of elements in a chemical change. Law of conservation of mass is followed by elements during a chemical change.