We did a lot in chem this week.

SG chem 2a

We had a pretty intense week in SG chem 2. We learnt a lot of new material and we are now getting ready for our next unit test (which will be on Friday, October 16th). We started of the week by doing a work sheet about relative mass and the mole. This is when we first even started talking about moles, and I didn't really understand what it meant. The worksheet was spilt up into three models and we worked in our table groups and after model one things got a little easier. Most answers were pretty easy and math was always simple, but you had to make sure you didn't over think some of the concepts.  We white boarded the last part of model three and once we figured out that everyone had the right answer we moved on. I'm glad we started with this packet, because it helped us flow into the next one.

The next worksheet went more in depth about moles and what they are. We learnt that one mole equals 6.02 x 10^23 and since it was hard to imagine that number, there were different analogies on the page to help us visualize it better. For example, it said that one mole of rice grains is more grain than the number of all grain grown since the beginning of time! Another one said that one mole of marshmallows (standard 1in^3 size) would cover the United States to a depth of 650 miles. That is INSANE! But also, SO cool to think about. Anyways, there were 3 problems on the bottom for us to do and we worked together as a class learning about unit conversions and the right way to do them. I think if you follow the method you showed us in class, they really aren't bad at all. 

The next thing we started was a lab. It was called the Empirical Formula Lab and we started off by taking the mass of the labeled beaker, then the mass of the beaker + zinc, and then we heated it up and took the mass of the beaker + zinc chloride and we kept doing that. 

Then we took some observations and then worked on the problems on the back which, thanks to the earlier worksheets, were pretty simple. 

 The last thing we did was white board all our answers on the front board and we came to the conclusion that the Empirical Formula that we all got was ZnCl2.

(here's a cute selfie of table 6 all being safe and working hard!)

The last thing we worked on this week (and got homework on) was a mole practice sheet. It's just a bunch of different and random mole problems, and personally, I think they're pretty easy. We did the first couple together as a class, and like I said earlier, if you do it the way you showed us, it's not that bad. However, we have a quiz on Monday, so this worksheet was good practice. 

We did these together

And this one we did as a table.

Anyways, that was pretty much all we did this week and we did get some more practice for homework this weekend, but I think it'll be good for us and help us prepare for the quiz. Can't wait for next week!! :) 

SG chem 2a

This week in SG chem was very exciting!! We started off monday and tuesday reviewing for our unit 4 test. We had a review guide and we pretty much just went over the stuff we've been working on for the past couple of weeks. We went over the differences between elements, compounds, mixtures, and pure substances (For example, we know that a compound can be separated by electrolysis, a mixture can consist of two or more elements in a fixed mass ratio, and more!!) After that we went over how to sketch particle diagrams.

 

All of this was fairly easy except at first I didn't really understand why diatomic meant. I knew that if they gases were diatomic, the volumes of the gaseous product would double, but I wasn't 100% what it really meant. However, I know that the "di" in diatomic means 2, so there's 2 atoms instead of 1 in normal gases.  The last things we reviewed were different mass composition problems and sketching graphs. 

 

Again, both of these things were straightforward and since we spent so much time white-boarding and learning the material, it was a breeze! We took our test and I honestly thought it went really well, but turns out I ended up getting a 31/34, so I need to go back and check what happened with that. 

The very next day we started unit 5 (which is about counting particles) and we immediately got the unit objectives. The first one was about Avogadro's hypothesis, but that was review from last chapter The second object, however, was a little different. It says, "Use experimental data to determine relative mass of two objects." At first, I was really lost. I remember learning a little about it in chem 1 (but I took that class as a freshman, so it was kind of long ago), but then we did a worksheet and it started to make a little more sense. 

We learnt unit conversions, and one main thing I got out of this worksheet (along with many other things) was that in order to find the average weight, all you have to do is weigh the box, then the stuff inside the box, then weight them together, take the difference and then just divide by the average! So easy! I would have never thought of that until we did this activity. The back of the worksheet (more specifically, the last problem- the extension) was the most interesting to me. It was really cool how we connected everything we had just learnt with the stuff we learnt in the last unit. It was also cool, because this was how the scientists way back then did things and it was awesome to see something from their perspective and actually figure out the reasoning to what they thought back then. 

The last thing we did this week was a worksheet. It was about molar masses of the elements. This worksheet was pretty similar (lots of math so that sucked!!), but we didn't have a chance to finish it in class, so I'm sure we will go over it in greater detail tomorrow in class. The last couple questions are all reflection questions, so I don't think it'll be too difficult. 

Can't wait for this new week! Love science! :)