An example of a physical change is a) cooking an egg. b) folding paper into a frog. c) rusting iron in an old bicycle. d) reacting baking soda and vinegar to make a volcano.

Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in the n=3 level to an orbital in the n=7 level.

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.

How does a catalyst increase the speed of a reaction? a. the catalyst eliminates the activated complex stage, allowing products to form immediately. b. the catalyst lowers the energy level of the reactants, making it easier for them to react. c. the catalyst makes it easier for the activated complex to form, lowering the activation energy. d. the catalyst raises the energy level of the products, making the reaction finish sooner. reset next