The students in Ms. Ramirez's science class are classifying different types of reactions. They have divided the reactions into two columns, as shown below. Use the table to answer the questions that follow. Column A Column B
Baking cupcakes Dissolving salt in water
Burning a log Boiling water
Frying an egg Freezing juice
Iron rusting Sawing a board in half
Why are the reactions listed in Column A classified as chemical reactions?
A.
The changes do not affect the materials' characteristics.
B.
The changes to the materials can be easily reversed.
C.
They changed the properties of the materials.
D.
They changed the shape of the materials.

Aflask with vinegar in it has a mass of 160 grams. a balloon with baking soda in it has a mass of 40 grams. the balloon is attached to the flask to seal the opening and the vinegar and baking soda mixes. the balloon inflates to a large volume. what will the total mass of the balloon and flask be after the balloon inflates? explain. a) less than 200 grams because the solid baking soda disappears. b) 200 grams, because all the atoms remain in the balloon or flask. c) more than 200 grams because the size of the balloon is so much larger. d) less than 200 grams because gases such as the one in the balloon are lighter than solids and liquids.