SCIENCE
CHEMISTRY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
The elements combine to make molecules
|
|
|
The material increases mass
|
|
|
The material changes into another type of material
|
|
|
The material changes form but stays the same molecule
|
Detailed explanation-1: -A physical change is a change to a sample of matter in which some properties of the material change, but the identity of the matter does not. When liquid water is heated, it changes to water vapor. However, even though the physical properties have changed, the molecules are exactly the same as before.
Detailed explanation-2: -In a physical change the nature of the substance, the particles of which it is composed and the numbers of particles remain unchanged. In a chemical change the properties of the new substances are different from the original, the particles are different and the number of particles can change.
Detailed explanation-3: -The same amount of matter exists before and after the change-none is created or destroyed. This concept is called the Law of Conservation of Mass. In a physical change, a substance’s physical properties may change, but its chemical makeup does not.
Detailed explanation-4: -The difference between a physical reaction and a chemical reaction is composition. In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.
Detailed explanation-5: -Physical: boiling and melting are physical changes. When water boils no bonds are broken or formed.