Question

Theoretical Questions
A. Answer the following questions in brief.
1. Define atom.
2. What is the difference between an element and a compound?
3. Why is water called a universal solvent?
4. How can we dissolve extra sugar in water?
5. What is the main difference between physical and chemical cha
B. Answer the following questions in detail.​

Answer 1

1.An atom is the smallest unit of ordinary matter that forms a chemical element. 

2.An element is a material that consists of a single type of atom while A compound consists of two or more types of elements held together by covalent or ionic bonds.

3.Water is called the "universal solvent" because it dissolves more substances than any other liquid. 

4.Sugar dissolves in water because energy is given off when the slightly polar sucrose molecules form intermolecular bonds with the polar water molecules. The weak bonds that form between the solute and the solvent compensate for the energy needed to disrupt the structure of both the pure solute and the solvent.

5.Physical change-When a substance undergoes a physical change, its composition remains the same despite its molecules being rearranged.

Chemical change-When a substance undergoes a chemical change, its molecular composition is changed entirely. Thus, chemical changes involve the formation of new substances.