Struggling with Chemistry - page 2
by mswtruth 2,079 Views | 13 Comments
Hello all...I have never taken Chemistry and I feel like I am struggling with my first course. It's general and organic chemistry. I just took my first exam today and expected to do so well. I did on 85% if it. But then came the... Read More
- 0Feb 16, '13 by mswtruthOh I didn't get an 85% on the exam I just understood most of it. I ended up getting a 77% on it. I am so proud of that C+. I really thought I had failed. I know if I study more, practice more...I can get an A in this class. 3 more exams. All I can do is keep trying my best.
- 0Feb 16, '13 by SopranoKrisI find the most difficulty people have with Chem is when they don't write out every part of an equation. It may seem silly to always annotate when you know what the variables are. However, if you always write everything out, you can't go wrong.
For example: If you're given the equation Na2O + 2 HCl ==> 2 NaCl + H20 and given the question if you have 18 grams of Na2O, how many grams of NaCl will result?
You need to write down for every mol of Na2O, you have 2 mols NaCl (you'll need this ratio later). Then set up your dimensional analysis, making sure you annotate every compound & unit:
18 g Na2O x (1 mol Na2O/62 g Na2O) x (2 mols NaCl/1 mol Na2O) x (58 g NaCl/1 mol NaCl) = 34 g NaCl
By writing down all your units & compounds, you can cancel g Na2O, mol Na2O and mol NaCl to end up with g NaCl.
While this is just a simple example, it really comes in handy when you move in to more complicated equations (e.g. kinetic theory, ideal gas law, etc.) For example, the constant R that is used in the ideal gas law is 0.08206 (atm*L/mol*K). If you write down the units, it's easy to make sure you cancel the proper units to arrive at your answer.
It was stated above, but I'll say it again: Khan Academy is a GREAT site for all things science!
- 0Feb 18, '13 by mswtruthSopranoKris I love Kahn Academy and have been using it more frequently. I'm with you on writing everything out. I'm the same with Algebra. I need to write it all out so as to not miss any steps in my equation. I think I need to just practice practice practice now that I'm studying Moles and Solutions. I have 2 full weeks before my next exam and I plan on just studying my equations and solutions everyday and go to tutoring on campus even just to review. I hope that can help me score an A. If I want an A in the class I don't have any room left for much error.
Anyone ever watch any powerpoints or documentaries on chemistry that helped?
- 0Feb 18, '13 by phoenixnimI agree with practice and practice. And I have to say that the factor label method helps a lot to visually see what needs to be cancelled out in the equation in order to get the correct units in the end. I have my first exam tonight. So far I'm feeling mostly good about it, but the first exam is always nerve racking because of not knowing how hard of a test design to expect from the teacher.
I'm so far maintaining an A with lab and homework. Hopefully the semester can end that way.