- Joined
- Dec 18, 2006
- Messages
- 694
- Reaction score
- 1
- Points
- 4,571
- Pre-Dental
-
Scholarship Access: Becoming a Student Doctor course
Free access to comprehensive medical school prep. Eligible students include AAMC FAP recipients and HS graduates from underserved areas. Apply today. -
Advice for Stoichiometry???
- Thread starter Cofo
- Start date
when in doubt, convert to moles
if you want to pm me the problems I'll do what I can to solve them and explain how to do them. I am leaving to go to work so i wont be home until 10:30 though
if you want to pm me the problems I'll do what I can to solve them and explain how to do them. I am leaving to go to work so i wont be home until 10:30 though
- Joined
- Aug 24, 2005
- Messages
- 687
- Reaction score
- 4
- Points
- 4,591
Whatever units you have on the top left must always be carried to the bottom right. For example:
1 mole Hydrogen X 1 gram Hydrogen/1 mole Hydrogen
or...
3 grams H2O/5 grams Oxygen X 1 mole H2O/18 grams H2O
It is hard to see it over the computer; write out the equations above on paper, but use a straight bar for the fractions (not a "/"). You will see what I'm talking about when I say that the units from the top left have to transfer and be the units on the bottom right. This rule is ALWAYS used. Once you figure this out, you can do almost any stoichiometry problem without hardly even thinking about it.
1 mole Hydrogen X 1 gram Hydrogen/1 mole Hydrogen
or...
3 grams H2O/5 grams Oxygen X 1 mole H2O/18 grams H2O
It is hard to see it over the computer; write out the equations above on paper, but use a straight bar for the fractions (not a "/"). You will see what I'm talking about when I say that the units from the top left have to transfer and be the units on the bottom right. This rule is ALWAYS used. Once you figure this out, you can do almost any stoichiometry problem without hardly even thinking about it.
- Joined
- Sep 1, 2006
- Messages
- 371
- Reaction score
- 3
- Points
- 4,531
For the basic concept of stoichiometry, try to use analogies that you can relate to. If you like cars, for example, you know that one car has 4 wheels. If each wheel has 5 lug nuts, then you can convert from cars to lug nuts by multiplying the number of cars by 4 (wheels/car) and then by 5 (lug nuts/wheel). The cars and wheels cancel, leaving you with lug nuts.
- Joined
- May 31, 2007
- Messages
- 103
- Reaction score
- 0
- Points
- 0
- Dental Student
Yep, I second Danny
Also, at some point you should realize that you are just dealing with mathematical proportions except your're on chemistry's playground. Stoichiometry is just math ratios in a chemical context.
Also, at some point you should realize that you are just dealing with mathematical proportions except your're on chemistry's playground. Stoichiometry is just math ratios in a chemical context.
Here is a little picture to help you visualize what Fuji was saying. I hope it comes through ok...
What I did when I started gchem1 was go in and talk with my prof. He was pretty helpful and understanding. I didn't have a clue what a mole was or what stoichiometry was either. Just put a lot of time into it...get help from the science learning center or something...just get help, it will click then it will be easy for you. Good luck!
View attachment chemhelper.bmp
What I did when I started gchem1 was go in and talk with my prof. He was pretty helpful and understanding. I didn't have a clue what a mole was or what stoichiometry was either. Just put a lot of time into it...get help from the science learning center or something...just get help, it will click then it will be easy for you. Good luck!
View attachment chemhelper.bmp
