How can i make new substance from old substances?

2points what is the job of a scientist? a. to answer ethical questions. b. to write laws based on his or her knowledge. c. to ask and answer scientific questions. d. to ignore facts that do not support his or her theory.

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

What causes the appearance of lines in a emission spectrum