Chemists can use moles to calculate: a. how much of the products are needed and how much reactant will be made. b. how much product will be made, but not how much of the reactants are needed. c. how much of the reactants are needed and how much product will be made. d. how much of the reactants are needed, but not how much product will be made.

Can anyone explain 1. review your spectrometry data and use the known elements to identify the star's composition. which unknown elements make up this star? justify your element selections. 2. in parts i and ii of the lab, what happened to the electrons of each element to produce the different colors of light? explain your answers using important terms from the lesson and information provided in the laboratory. 3. stars composed of heavier (more massive) elements are often slightly older than stars made predominantly from hydrogen and helium. based on your data, is the newly discovered star a younger star? explain your answer.