Which of the following most likely happens during a chemical change?

a. no new substances are formed.
b. properties of a substance remain unchanged.
c. composition of a substance is same as before.
d. different atoms than before are introduced after the change

How has the scientific community addressed the safety of chemicals? a. chemicals are repeatedly tested, even those that have existed for a long time. b. existing chemicals are tested if they have never been tested before. c. chemicals are tested if they are suspected to have caused a problem. d. only new chemicals are tested.

Which piece of equipment would me most useful for measuring the volume of some water? a. pan balance b. graduated cylinder c. tweezers d. flask quick

Melting and boiling are endothermic processes. this means that these processes absorb energy from their surroundings in order to occur. use this information and the data you collected in the phase change gizmo to describe what happens to the temperature of water when you boil it, then explain why this result occurs.