How does the mass of the reactants compare to the mass of products

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

The identities of substances are the same before and after which type of change

Scientists often have to deal with numbers that are either very large or very small. for example, the radius of the sun is approximately 696,000 kilometers, while bacterial cells are as small as 1.9 × 10-4 millimeters. express each number in an alternate form.