Which statement explains how balanced chemical equations obey the law of conservation of mass? Choose the correct answer.

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.

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

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