Monday, October 25th

In chemistry today, we started out by receiving our grades. Mr Henderson also reminded us of our Test on Thursday along with our delicious bookmark which is due at the end of the unit. Then we moved on to our lesson of the day which was mass composition and empirical and molecular formulas. Our lesson for today was on the packet page 13. We started out by finding the molecular or empirical formula’s of certain compounds with a given molar mass. As an example in the compound Octane, the molar mass was 114.2 g/mol, and the molecular formula was given to be C8H18. Mr. Henderson then explained that the empirical formula was C4H9 because it was the simplest ratio of the molecular formula.

In a second example, we were given the compound Benzene and the molar mass was 78.1 g/mol. The empirical formula CH was given and there are many possibilities for a molecular compound from this formula, so the Mr Henderson explained how you can find the molecular formula through the molar mass. For this problem we found that the mass of Benzene was six times that of the empirical formula, so therefor the molecular formula would be C6H6.

We then did a word problem together where we had to determine the empirical and molecular formula of an unknown carbohydrate when given the percent ratios of the elements and the molar mass. We solved this by assuming that that there was 100.00g of this substance, then we multiplied each of the percentages by their molar masses and from this we got the empirical formula which we compared with the molar mass to get the molecular formula.

Finally we finished the class with the Formula of a Hydrate Lab. In this lab we had to determine the chemical formula of the hydrate of copper sulfate by weighing the copper sulfate before and after we burned all the moisture out of it.

August 31, 2010

Class today started with Mr. Henderson speaking on the subject of our blogging. We viewed the blog posted by Will and Mr. H spoke on logging into the blogging site with our school email.

Then we reviewed our homework in our unit 1 packet. Our homework was on chapter 1.1 of our textbook on the subject of types of matter. But before we got to look at the answers, Mr. Henderson covered them and reviewed some key terms and points of the section first. Some of these points were the learning progression of our year in chemistry, which will hopefully end with us being enlightened on the subject. We also reviewed some key terms such as matter, a mixture and a compound. After the review, we finally checked our work.

After reviewing our homework, the class turned to page 2 of our packet. Then Mr. Henderson helped us fill in the chart were we identified whether the drawing was showing an element or a compound, and if it consists of atoms or molecules. The class learned that if a substance is made up of only one type of matter it was an element, and if a substance is made up of different types matter it was a compound. Also if a substance is a compound then it only consists of molecules. But if a substance is an element then it can be made up of either atoms or molecules. As Mr. Henderson was teaching he was always referring to the giant periodic table on the wall to help get us a more visual idea of what makes an element an element. Then the rest of the page was assigned for homework.

The rest of class was dedicated to us finishing our Observation and Experimentation Lab. In this lab we were supposed to observe the changes which occurred when we mixed the chemicals calcium chloride, sodium bicarbonate, and a solution of phenol red indicator. When the chemicals were mixed some of the different mixing of chemicals had reactions such as the inflation of the bag which showed fumes were released, the bag getting hot, and/or a color change. Then time ran out and the rest of the lab was assigned for homework.

Today's fifty minutes of class was very educational and productive.