When someone is injured, responding medical personnel may use either hot packs or cold packs to treat the injuries. These are examples of miniature chemical reactions. Using hot packs and cold packs as an example, explain the terms endothermic reaction and exothermic reaction.

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line

How many liters of oxygen gas, at standard temperature and pressure, will react with 35.8 grams of iron metal? 4 fe (s) + 3 o₂ (g) → 2 fe₂o₃ (s)

The number at the end of an isotope’s name is the number.