Ateacher makes the following statement.

“gasoline boils at a relatively low temperature (about 150°c). the kerosene is removed at around 200°c, followed by diesel oil at 300°c and fuel oil at around 370°c.”

what topic is the teacher most likely talking about?
a. distillation of a mixture
b. filtration of a pure substance
c. evaporation of a mixture
d. sorting of a pure substance

The correct answer is option a.

Explanation:

According the question, boiling points of different liquids are discussed which means that if we take all these liquids in single mixture we can separate them from each other on the basis of their difference in boiling point. And the technique which employs this principle is distillation process.

Hence, we can say teacher is most likely talking about distillation of a mixture of oils.

Distillation is a process which is used to separate mixture of different liquids from each other. In this process, during the course of boiling of mixture liquid compound with lower boiling points vaporizes first leaving behind the liquid with higher boiling point behind.

And vapors of boiled liquid are condensed down in a separate container for the collection.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.