1. How to read and follow directions correctly
2. How to find the mass of a substance
a. find the mass of the container, the mass of the container + the substance and subtract to find
the mass of the substance
b. put scratch paper on the electronic balance, press "tare" or "re-zero", then add as much
substance as you need
--BE SURE TO MEASURE THE MASS CAREFULLY!! Record it to at least the .01g--
3. How to find the temperature of a substance
a. place the thermometer in the substance, being sure NOT to touch the sides or bottom of the
container that the substance is in
b. carefully read and record the temperature to the nearest .1 oC
4. How to find the volume of a substance
a. place the substance into a graduated cylinder, read and record the volume to the nearest .1m
b. put water into the graduated cylinder, read and record the volume of the water to the nearest
.1ml, add your substance and read and record the volume to the nearest .1ml again, then
subtract to find the volume of your substance
5. How to find experimental error
a. subtract your experimental value from your theoretical value, divide the difference by the
theoretical value and multiply by 100% (this shows how far from theoretical your experiment was)
HOW TO TAKE A CHEMISTRY TEST
--If it is a scantron test (rare)
1. Look for the questions you know best; answer them first; then go back to the more difficult ones.
2. Try to eliminate one or more of the possible answers (NOT BY CROSSING THEM OFF THE TEST)
3. Remember your first guess is often likely to be right; don't change an answer unless you are sure
of your new answer (second-guessing will most likely mess you up)
--If it is a problem test (most frequent)
1. Look for the questions you know best; answer them first, then go back to the more difficult ones.
2. For ALL questions, be sure to write down all given information first (this does NOT mean "copy
the problem") Label and identify all given information using the correct variables and units.
3. Include any and all equations that you use.
4. Show all the steps you use to solve the problem--did you multiply both sides by 2? Did you
divide by density? SHOW ALL WORK means exactly that. Your work should look a lot like what
I do in class when I work a problem out for you.
5. Watch for significant figures. Go back to the original information given in the problem to look for
how many sig. figs. you answer should have.
6. If you get stuck on a step or are stopped because you're missing one piece of information, make
something up, write down what you've made up (explain to me that you made it up) and continue
from there. You will lose points for the missing information, but if you do the rest of the steps
correctly based on that wrong information, you will get credit for the rest of the problem.
--If it is an essay test (or an essay question)
1. Answer the questions clearly and concisely using the correct terminology.
2. I ask for essay answers, not "BS-ay" (B.S. as in bologna sandwiches). Do not give me a long answer
that is completely irrelevant. Some students appear to believe if they write a lot, it will be worth a lot.
I DO read these and do not respond well to lots of nonsense. The more clear you are about a concept,
the more able you are to explain it in fewer words. I am actually looking for the briefest, most
complete answers.
3. Here's the test for whether your explanation is good, or not. Can a sixth grader read your answer and
know what you are talking about? Would someone who doesn't take ( or teach ) Chemistry be clear
on the concept you are explaining just from reading your explanation? If not, your answer is not good
enough. (BIG HINT: if your defense of your answer contains the words "but you know what I meant" it
wasn't a good answer)
4. Here's an example of a poor essay answer. Question: Explain solubility. (not actually a question ;-)
Poor Answer: Is something soluble or not.
Better answer: Solubility is a measure of how well a substance will dissolve--or break
apart into its ions--in a solvent. It is partly determined by the type of solute and solvent;
a polar solute will dissolve more completely in a polar solvent, for example. Ionic
substances will also dissolve well in a polar solvent due to the attraction between the
charged ends or sides of the ionic solute and the oppositely charged ends of the polar
solvent.
In the first answer, there was actually no explanation at all. There was something sort of resembling a
definition, but this was supposed to be an explanation of the word, not a definition. A definition may be
part of an explanation, but it is not an explanation.
You should also avoid using the word, or derivatives of the word in your explanation.
5. I do NOT want an answer that resembles the book's definition.
HOW TO STUDY FOR A CHEMISTRY TEST
1. Go over all warm-ups since the previous test. The best idea is to re-work all of the problems (without looking at the answer) then check to see if you got the right answer. If you did not, practice more on the same topic. Use the problems at the end of each chapter--remember the blue numbered ones have the answers in the back of the book.
2. Skim through the chapter. Look at the diagrams, tables and examples. If there is something unclear to you, check your notes to see if you have notes on that particular topic.
3. Work with someone who is doing well in class (or, if you're doing very well in class, work with someone who is doing poorly). Spend your time discussing the problems, working them out--without looking at each other's paper--and checking your answers with each other and the back of the book, if possible.
4. Come in before school--NOT THE DAY OF THE TEST--to see me if you need additional help.
If you have been diligent enough to read all of this, here is another reward--on your next test write me a note at the end of your test, telling me that you read this (DON'T TELL ANYONE ELSE ABOUT THIS) SORRY; you missed this opportunity--it expired May 12th after being here for 3 months!!