Evidence Of Physical & Chemical Changes

Explanation
The presence of gas being produced is evidence of a chemical change because it indicates that a chemical reaction has occurred. In a chemical reaction, new substances are formed with different properties than the original substances. Gas production is often a result of the formation of new compounds or the release of gas molecules from a compound. This release of gas signifies a chemical change taking place.

Explanation
The experiment described in the question is an example of a physical change. A physical change is a change in the form or state of matter without any new substances being formed. In this case, the sugar cube dissolved in water, which is a physical change as the sugar molecules dispersed evenly throughout the water. However, when the water evaporated, the sugar returned to its original form, indicating that no new substances were formed. Therefore, the correct answer is Physical Change.

Explanation
A chemical change involves a rearrangement of atoms and the formation of new substances. This process is often accompanied by the release or absorption of energy. Once a chemical change has occurred, it is usually difficult or impossible to reverse it and return the substances back to their original state. This is because the new substances formed have different properties and characteristics than the original substances. Therefore, the statement that a chemical change cannot be reversed easily is true.

Explanation
The options provided describe different physical changes. The fact that an object can be reversed suggests that it undergoes a reversible change, which is a characteristic of physical changes. The object freezing is also a physical change, as it involves a change in state from a liquid to a solid. However, the production of light is not typically associated with physical changes, but rather with chemical changes or reactions. Therefore, the correct answer is that a light is produced.

Explanation
The science experiment described involves the combination of vinegar and baking soda, which results in a fizzy reaction and overflow of gases and bubbles. This indicates a chemical change, as a new substance is formed through a chemical reaction between the vinegar (acetic acid) and baking soda (sodium bicarbonate). The formation of carbon dioxide gas causes the fizzing and bubbling, indicating a chemical change rather than a physical change or fusion change.