Whenever there is a change of state, such as a solid to liquid or liquid to gas, heat energy can be added without a temperature change because
a) the added energy is not needed.
b) the energy is lost to the system.
c) the change of state requires energy.
d) the energy is lost to the atmosphere.

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

How do i turn 2 s into one in the products