Which of the following is a true statement about the differences between electromagnetic and mechanical waves? a electromagnetic waves are caused by vibration of particles and mechanical waves are caused by frequency, not amplitude. b electromagnetic waves are considered a periodic disturbance and mechanical waves are considered a disturbance. c electromagnetic waves require a medium to travel in and mechanical waves do not require a medium. d electromagnetic waves travel in a vacuum and mechanical waves do not travel in a vacuum.

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.