Monday, October 18, 2010

Who is Amadeo Avogadro? Why, only the most famous scientist ever! Why is he so famous? He thought of the mole, that's why. The mole is a scientific unit. It is used in measurement, mostly in chemistry. The mole is abbreviated as "mol". But why is this significant? Today, we started Unit 3. Unit 3 focuses on stoichiometry, or the science that deals with the quantitative relationships that exist between products and reactants. (conversion factors) The number mole, is mathematically written as 6.022 x 10 to the 23rd

To begin our class today, Mr. Henderson passed back our grade reports, with the Unit 2 Test inscribed upon its face. Mr. Henderson also told us about the National Mole Week recently declared by President Obama. With that, we began class.

We took some notes and filled out a leaf of paper in our Unit 3 Packet. It focused on finding the number of moles of a certain atom in some situations and and finding the number of atoms in others. These are two very different ideas. Using conversion factors we learned earlier, we were able to make short work of these four problems we were given. Mr. Henderson also showed us how to find the number of atoms in a certain mass of an element. For example, let's take 12.01 grams of carbon. The number of atoms for this amount of carbon would be 6.022e23. (1 mole) How did we get that? The average atomic mass of carbon is 12.01. If you have an atom, with its average atomic mass in grams, just put down one mole as your answer. However, if the mass in grams is slightly smaller or larger than your given atom's AAM, you take the 6.022 from the mole and divide or multiply accordingly. For example, let's say you had 20 grams of calcium. The AAM for calcium is about 40. Because this is half, you would take 6.022 and divide by two. Your answer shall be 3.011 x 10 to the 23rd. (you keep the last part of the number)

To end the class, we started our MR1 lab. (after getting new lab groups and moving to new seats) This is the H2O challenge lab. We have to count how many molecules there are in a sample of water. Since we cannot see molecules, we must count them in a different way. By using the mol, of course. We add the AAM of two hydrogen atoms to the AAM of one oxygen atom. However, not everyone finished this lab in class today and Mr. Henderson will let us finish it tomorrow. For anything else check his website.