Which of the following is not a physical change?

sublimation

deposition

combustion

evaporation

Which element is least likely to undergo a chemical reaction

The number of moles of a given mass of a substance can be found without knowing its molecular formula or molar mass. true false

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