SG Chem 2 - Fourth Blog

This week in Chem 2 we were introduced to a new unit of measurement that is used often in chemistry. This new unit is called a mole and can represents 6.022 x 10^23 atoms/particles. We were also reminded of that fact that atoms combine in simple, whole-number ratios. We learned/re-learned  these two things separately but then later in the week we were able to bring both pieces of information together to solve certain problems that were given to us.

For example, on Monday we learned the basic concept of what a mole was. We completed a sheet that started us out with units of measurement that we already knew, such as a dozen eggs. Then, after solving problems with the dozen eggs the sheet applied what we knew about that to teach us how to calculate things with moles.

On Wednesday and Thursday we did a lab the involved combining zinc and chlorine. We combined the two elements then slowly evaporated the water (that was brought into the reaction through heating) away to get just the combination of zinc chlorine. By doing this we found that the mass ratio was approximately a 2:1 ratio. Each table, no matter how much zinc chloride they had, got the same ratio.

The zinc and the 3M HCl before combining

The Zinc and 3M HCl chemically reacting once combined

The chemical product of the combination of zinc and 3M HCl to form zinc chlorine
(Being put on ring stand to heat away any water)

The chemical product of zinc chloride when heated to get rid of the water

We took the information from the Monday worksheets and the results from the lab on Wednesday/Thursday to complete Unit 5 Worksheet 2 with sample containers. This sheet involved finding the amount of moles or atoms in a certain amount of a given element. For example it asked us how many moles of table sugar were in bottle two (sugar in bottle 2 = 118.6g). Because we know that 1 mole is the elements atomic mass (from the sheets on Monday) and that atoms/elements combine in whole number ratios (from our lab) we were able to calculate the amount of moles in each elements. We could even go farther and find the amount of atoms in the in the given element based on how many moles there were because 1 mole is 6.022 x 10^23.

I think this week I participated more in class. I took leading rolls in our lab that we did and I worked on asking my table mates for help when I didn't understand things. I also am trying to help my friends in the other chem 2 class (fifth hour) who are confused on things that I understand.

I think I definitely understand this unit and the things that we did in class a lot better than anything we did in unit four. That being said, I still need to work on the calculation problems. I understand the simple ones and I understand the concept of bringing down the unit so they can cancel out. What's hard for me is when the problem starts giving a lot of details with a lot of different units and lots of numbers. For example the last few questions that were on the homework sheet. They give a lot of detail and I'm unsure of how to know which ones to use and how to use them. Because of this I would rank my understanding of this week as an 8/10.