Q: a: sarah and maria made a telephone using two cans and a string. it was a very long string. maria went upstairs in her house and sarah stayed downstairs. maria spoke softly into the can. "i can hear you! ' sarah said back. how can this happen? a) sound waves travel through a vacuum. b) sound waves travel from high to low. c) sound waves travel through solids like the string. d) maria talked so loudly that sarah could hear her without the phone.

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.