What must be done to calculate the enthalpy of reaction? Check all that apply. The first equation must be halved. The first equation must be reversed. The second equation must be halved. The second equation must be reversed. The third equation must be halved. The third equation must be reversed.

What can be added to the examples section of each circle? endothermic: ice melting into water, and a heat pack becoming warm exothermic: a glow stick glowing, and fireworks exploding endothermic: ice melting into water, and an instant ice pack turning cold exothermic: fireworks exploding, and gasoline burning endothermic: a glow stick glowing, and a heat pack becoming warm exothermic: an instant ice pack turning cold, and ice melting into water endothermic: gasoline burning, and an instant ice pack turning cold exothermic: ice melting into water, and an instant ice pack turning cold

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

Structure of the atoms: discovery of the nucleus in 1909i need answering all of these questions