Question

penny placed a tablet of baking soda in a cup of water. the tablet immediately began to bubble, fizz, and eventually dissolve.
did a physical or chemical change occur and how do you know?
oa chemical; the tablet gave off a gas in the form of bubbles
ob chemical; the fizzing sound indicates a new substance was formed
oc physical; the tablet only dissolved in the water and formed a mixture
od physical; the water can be boiled off and the tablet residue would be left

Explanation:

A chemical change involves the formation of new substances. When the baking soda tablet reacts with water and gives off gas (bubbles), it indicates a chemical reaction. A physical change would not produce a new substance. Option A is incorrect as just giving off gas (bubbles) is not the full - fledged reason for a chemical change. Option C is about a physical change (dissolving to form a mixture) which is not the case here. Option D is also about a physical change (boiling off water). The fizzing sound is an indication of gas release during a chemical reaction which leads to the formation of new substances.

Answer:

B. chemical; the fizzing sound indicates a new substance was formed