Identify the changes and give an appropriate reason for your answer.
a. Melting of ice
b. Curdling of milk
c. Digestion
d. Bursting of crackers
e. Breaking of glass
Answers
A. As an ice cube melts, its shape changes as it acquires the ability to flow. However, its composition does not change. Melting is an example of a physical change .
B. the entire process that the reaction between lactic acid and milk involved breaking of bonds and forming of new bonds Hence, it is a chemical change .
C. Digestion of food is a chemical change because it involves various chemical reactions.
D. the reactant and the state changes along with its physical properties and chemical properties, the explosion of crackers are considered as a chemical change.
E. Breaking is a physical change because the shards are still glass, but it can't be easily made whole again.
Answer:
a. Physical change.
As ice can be melted and frozen back to ice.
b. Chemical change.
Curd cannot be brought back to its normal form after it has become curdled.
c. Chemical change.
As complex consumed food is turned into nutrient providing energy for the body and cannot be reversed back to food intaken.
d. Chemical change.
As crackers burst, the chemicals present inside combust to form Ash and various other effects which cannot be brought back together after combustion.
e. Physical change.
Even though broken glass cannot be brought back together or reversed, but when glass is broken, no new substance is formed for this to be considered as chemical change.
Hope this answer helps...