Question

practice: identify the following as being true or false to the left of the sentence.

1. a change in size or shape is a physical change.
2. a chemical change means a new substance with new properties was formed.
3. an example of a chemical change is when water freezes.
4. when platinum is heated, then cooled to its original state, we say this is a physical change.
5. when milk turns sour, this is a physical change because a change in odor and taste indicates a physical change.

Explanation:

1. Physical changes alter size/shape without new substances.
2. Chemical changes produce new substances with unique properties.
3. Water freezing only changes state, no new substance forms.
4. Platinum returns to original state after heating/cooling, no new substance.
5. Souring milk creates new acidic substances, it is a chemical change.

Answer:

1. True
2. True
3. False
4. True
5. False