► How many moles of calcium are needed to react completely with 6 moles of H2O in the following reaction:

0.09 moles of sodium sulfate in 12 ml of solution

One student said that the investigation was not valid (a fair test). write a plan for the investigation that includes improvements to the method and apparatus

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.