Expert: Kevin - 10/26/2009

Question
Hello!  I am an eighth grade student and we have been asked to interview a chemist.  I would appreciate it if you could answer a couple of questions for me.

1. Could you explain how you find out what atoms are in different chemicals?
2. How does the knowledge of the structure of an atom help you in your job?

Answer
Hi Tommy,

Q1 You read the label on the jars! But if there is no label there are a series of tests that you do which will help identify the atoms present. Does it dissolve in water, acid, alkali, solvents?
How does it burn in a flame? What does its IR spectrum look like? Then there are lots of more discreet tests which will fully characterize any substance.

Q2. By knowing what atoms are present when a reaction is to be carried out I can calculate the proportions of each chemical required for the reaction. For example if I want to make water from hydrogen I know 2H2 + O2 -> 2H2O so for every 2 atoms of H2 I will need one of O2. From this knowing the atomic mass of the atoms I can calculate the weight of each component.

I hope this helps
Best wishes
Kevin