Chemistry
State whether the following statements are true or false. If false, write- the correct statement.
Desirable changes are meaningful, while undesirable changes are unfavorable.
During physical changes, the composition of the original substance is not altered, but the properties of the original substance are altered.
During a chemical change the composition of the original substance is not altered, and the change is irreversible.
Melting of butter and wax are examples of chemical changes.
The melting of ice is an exothermic, irreversible chemical change.
Answer
True
False.
Corrected Statement — During physical changes, the composition and properties of the original substance are not altered.False.
Corrected Statement — During a chemical change the composition of original substance is altered and the change is irreversible.False.
Corrected Statement — Melting of butter and wax are examples of physical changes.False.
Corrected Statement — Melting of ice is an endothermic, reversible physical change.
Related Questions
Explain in brief the involvement of energy in - physical & chemical changes.
Fill in the blanks with the appropriate words for each of the statements given below:
Germination of seeds is considered a …………… [physical/chemical] change.
If a change is permanent and irreversible, it is considered a …………… [chemical/physical] change.
Heating a piece of iron is considered a …………… [physical/chemical] change, while heating a piece of coal [carbon] is considered a …………… [physical/chemical] change.
Chemical changes may involve exchange of energy in the form of …………… & …………… [light/sound/magnetic /heat].
Change of milk to curd is a …………… [desirable/undesirable] change.
Match the examples of changes in List I with the correct type in List II.
List I List II 1. Expansion of a steel rod on heating A. Physical 2. Rotting of eggs B. Chemical 3. Milk turning sour 4. Tarnishing of copper 5. Separation of naphthalene from a mixture of naphthalene & sodium chloride Fill in the blanks with the correct words for each of the statements given below:
Sublimation is …………… [considered/not considered] a change of state of matter.
Sublimation involves a …………… [chemical/physical] change.
During sublimation a solid on heating turns directly into …………… [liquid/vapour] & on cooling back to …………… [solid/liquid].
Ammonium chloride, a sublimable solid undergoes …………… [synthesis/dissociation] on heating.
Sublimation of iodine is an example of …………… [physical/chemical] change.