Which changes of state require a decrease in energy

Which is true of the reactants in this displacement reaction? fe + 2hcl fecl2 + h2 a. the reactants are located to the left of the arrow in the chemical equation. b. the reactants contain 1 iron atom, 2 hydrogen atoms, and 1 chlorine atom. c. the reactants are the atoms, molecules, or compounds formed in the reaction. d. the reactants have the same physical and chemical properties as the products.

Mrs. smith ordered a root beer float (vanilla ice cream + root beer). mrs. smith noticed that the three states of matter (solid, liquid, and gas) all existed simultaneously in her root beer float. a. identify each phase of matter in the root beer float. b. describe the particles of all three phases of matter in the root beer float. (how are the particles arranged and moving? ) c. identify one phase change you would see in a root beer float and described what causes this change.

Frictional forces acting on an object are often converted into energy, which causes the temperature of the object to rise slightly.