Mr. H went over the relationship between particles, moles, and mass, and made a rather inappropriate pun involving molasses. Then, we solved problems 4 and 7 viewable below.
The rest of the period was spent on the Chew on This Lab and packet page 11. For the lab, we were going to determine the percent composition of sugar in gum. We measured the mass of the un-chewed gum with the wrapper and the wrapper by itself. While we chewed the gum to extract the sugar, we learned how to calculate percent composition. To do this, one had to find the molar mass of each element in a compound, divide that by the molar mass of the entire compound, and multiply the quantity by 100. After going through an example, iron (III) carbonate, Mr. H told us that page 11 would be a homework assignment due sometime next week.
At that moment, we had chewed our gum long enough to extract the majority of the sugar. We went to the scales in the back of the room to take the mass of the sugarless gum with the wrapper. Subtracting the wrapper's mass, we found the mass of the gum with sugar (un-chewed) and the mass of the gum without sugar (chewed). Subtracting the mass of the sugarless gum from the mass of the gum with sugar revealed the mass of the sugar in that one piece of gum. We followed the procedure for calculating percent composition and each of us got a unique answer. According to the manufacturer, this percent is approximately 80%, though this value can vary quite a bit. Mr. H made one last joke by instructing us on how to "properly" dispose of our gum: by sticking the piece under our individual desks.
Our homework is to do a WebAssign and finish our Unit 3 Delicious assignments. Our lab notebooks are also due at the end of class tomorrow, so don't forget!
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