Chemistry 2006/ 2007 Club*** - page 6

I am starting Chem II this semester. Anyone want to start a club??? :rolleyes:... Read More

  1. by   2bnurseforce1
    Hello all I am late joining but I am in Intro to Chemistry and I am having a problem with balancing formulas any help.
  2. by   droopy1592
    Post a reaction your having problems with and I'll go over it + balance it.
  3. by   klleo27
    Hello all. I havent started any classes yet but I need to take Mirco, A&P I&II, and Chem. I want to start one class in the summer but I am not sure which one to start off first (and it is going to be a summer course!) Any suggestions? It would be online at ccconline. So I would have to do labs at home. Thanks!
  4. by   laurawho7
    Anyone have any tips or tricks for memorizing formulas? Our Professor wants us to memorize poloyatomic ions and be able to write out formulas for our up coming tests. I am struggling with trying to memorize it all and could use some pointers from those of you who do well in chemistry. I have made a "practice quiz" but I am still hung up on memorizing the compounds!

    Thanks for all the help!
  5. by   droopy1592
    this is for butterfly and fnhopeful- i can't pm fnhopeful because your storage is too full... so i'll post the balancing stuff here.



    alright alright...

    look, the whole thing you gotta do in balancing equations is to make sure you have the exact same amount of each atom on each side of the arrow.

    n2 + h2 → nh3

    here, nitrogen gas and hygrogen gas are your reactants, and ammonia is your product... but look, you have 2 nitrogen atoms on the reactant side and only one on the product side.... so let's multiply nh3 by two so we can have equal amounts of nitrogen on both sides.

    n2 + h2 → 2nh3

    so what's wrong here? we have two nitrogen on both sides! now we're getting somewhere. so we have two nitrogen on both sides, and now two hydrogren on the reactant side but six hydrogen (multiply your stichiometry, or mole value 2 times your amount of hydrogen in the molecule, which is three) on the product side. something's wrong here. so in order to get six hydrogen on the reactant side, we need to multiply h2 by three.

    so now we have

    n2 + 3h2 → 2nh3

    so let's try again, you have two nitrogen on each side (n2 = 2n see, the 2 in n2 means that you have two nitrogen atoms in that molecule, but the 2 in 2n is you stichiometry value... or mole value). so we have equal nitrogen on both sides. count up the hydgrogen. 3 x 2 = 6 and 2 x 3 = 6 so we have six hydrogen on each side. this equation is now balanced. balancing equations is trial and error, it's not something you just look at and know where to start. you find an atom that has unequal numbers and you find a way to make it equal and you keep going until you figure it out. some can be tricky and you may even have to use fractions.

    try this

    hcl + sb2o3 -------> sbcl3 + h20

    now we've got 1 chlorine on the reactant side and 3 on the product side. this is just an abitrarily selected starting point. you can start anywhere.
    multiply hcl by 3 to get the same amount of chlorine on each side.

    3hcl + sb2o3 -------> sbcl3 + h20

    now i've got the right amount of cl, but the wrong amount of hydrogen on the other side (6 h on left, 2h on right)... hmm, how do i make 3h and h2 equal? i know, i'll find the least common denominator and make them equal. the lcd is 6, so i'm gonna find a way to get a total of six hydrogen on each side.

    6hcl + sb2o3 -------> sbcl3 + 3h20

    you're probably like "what the hell just happened?" well, this is a tricky one, so you've gotta get creative. i know we had equal chlorine on each side before, but we needed equal hydrogen also. that was the only way would could have fixed it and if we needed to go back to the sbcl3 and change it's value to make it balanced again then that's what we have to do. we need 6 chlorine on each side since we have 6hcl... so we multiply the sbcl3 on the product side by 2.

    6hcl + sb2o3 -------> 2sbcl3 + 3h20

    so now i've got 6h and 3 x h2 = 6 (on the product side), and 6cl on each side also so now i've got equal hydrogen and chlorine on each side. let's look at the oxygen. i have 3 oxygen on the reactant side and 3 on the product side... so oxygen is fine too. look at the antimony (sb, lol, weird name there) so because we balanced chlorine earlier sb is now also balanced. we got 2 on the reactant and 2 on the product side.

    so let's count everything up
    6 h on each side since 6h= 3xh2
    6cl on each side since 6cl= 2xcl3
    2sb on each side since sb2=2x1sb
    3o on each side since o3=3x1o

    so that equation is balanced....

    6hcl + 1sb2o3 -------> 2sbcl3 + 3h20

    remember, it's not done until you have equal amounts of each atom on each side.
    Last edit by droopy1592 on Feb 22, '06
  6. by   droopy1592
    Quote from laurawho7
    anyone have any tips or tricks for memorizing formulas? our professor wants us to memorize poloyatomic ions and be able to write out formulas for our up coming tests. i am struggling with trying to memorize it all and could use some pointers from those of you who do well in chemistry. i have made a "practice quiz" but i am still hung up on memorizing the compounds!

    thanks for all the help!
    there is no real trick, other than memorizing the one with the most oxygens (the -ate, except for iodate, bromate, and chlorate, then it's per-x-ate), how many oxygens it has and it's charge for each group. example, sulfur polyatomic anion sulfate is so4 with a negative charge of 2... so you know that sulfite has to be so3 with the same charge (-2). all of the -ates/-ites for each group (example: nitrate, nitrite have -1 and dihydgrogen phosphate/phosphite have -1) have the same charge, just different number of oxygens. -ates have 1 more oxygen than-ites so you have to atleast remember one for each group.

    for chlorate, bromate and iodate- remember that it descends in this order

    perchlorate clo4
    chlorate clo3
    chlorite clo2
    hypochlorite clo

    just change the name for the other two.

    perbromate bro4
    bromate bro3
    bromite bro2
    hypobromite bro1

    easy! do iodate yourself. remember hypo means under, -ate is higher than -ite, and per is the highest. each lower one has one less oxygen... per- usually means there are four oxygen atoms.

    all twelve of them have a single negative charge.

    also remember that carbon and nitrogen are in period 2 and can't bond to as many oxygen as sulfur and phosphorus. one of those oxygen will always want a double bond (truly a hybrid when you consider resonance-- which will take forever to expalin) which is why they don't really bond to four unless the oxygen is bonded to a halogen or hydgrogen already in addtion to carbon. maybe that can help you to remember that co3 is carbonate and no3 is nitrate (c and n in period 2) and phosphorous (phosphate is po4 and sulfate is so4) and sulfur are in period 3 so they can bond to more oxygen atoms since they have more freedom in the valence shell.

    i hope i'm making it too hard as some of this may be beyond what you've been taught in chem 1 and you will learn in organic chem.
    Last edit by droopy1592 on Feb 22, '06
  7. by   droopy1592
    Quote from klleo27
    Hello all. I havent started any classes yet but I need to take Mirco, A&P I&II, and Chem. I want to start one class in the summer but I am not sure which one to start off first (and it is going to be a summer course!) Any suggestions? It would be online at ccconline. So I would have to do labs at home. Thanks!
    Er, you can't do chem labs at home. At least I don't think you can. Usually the online universities have local complexes where you go to do lab but you do the lecture online. If anything, do Chem and A and P together, or just chem first... that way when you do micro you won't be lost.
  8. by   laurawho7
    Droopy thanks for all the info! You are a life saver! I just cant seem to understand the little nuiances of this stuff.

    If anyone knows of a book or website that does a good job simplifying this stuff I'd love the information. I do better with remembering if I can understand the why's not just dry memorization!
  9. by   droopy1592
    That's the thing about chemistry... it's the one subject you have to know why and you can't memorize it (well, maybe the polyatomic ions)
  10. by   droopy1592
    for naming inorganic molecules

    with ionic bond (metal from group 1 or 2 + nonmetal or polyatomic anion)

    cation (metal) name comes first and is named as element... anion name comes second
    example: sodium chloride, magnesium phosphate, potassium carbonate

    if it's ionic with a transitional metal:
    cation name comes first and is named as element followed by roman numeral to indicate charge on cation
    anion name comes second

    example:
    iron (ii) chloride
    iron (ii) oxide

    covalent compounds containing two elements
    first element is named as element
    second element is named as second anion
    the number of each element is designated using prefixes... mono, di, tri, tetra, penta, hexa, hepta, ocata, nona, deca (no need to use mono if there is only one first element as in carbon monoxide)

    example:
    dinitrogen tetafluoride n2f4
    tetraphosphorus decaoxide p4o10
    carbon dioxide co2

    for covalent acids (most are) the prefix hydro is used, the ending is changed from ide to -ic acid

    if the anion name ends with ate or ide end with -ic acid.
    if the anion name ends with ite end with -ous acid

    examples

    nitric acid hno3 aqueous
    nitrous acid hno2 aqueous
    sulfuric acid h2so4 aqueous

    remember that -ide is just a single nonmetal ending and -ate and -ite are complex anions
    Last edit by droopy1592 on Feb 22, '06
  11. by   droopy1592
    http://chemqueen.com

    This is my friend's chemistry site. There may be info here to help you.

    If you guys need anything else, don't hesitate to ask...
    Last edit by droopy1592 on Feb 22, '06
  12. by   droopy1592
    I'm going on vacation for a week so if you guys PM me or ask questions and don't get a response, you'll know why.
  13. by   Fox
    Hello Everyone,

    Have anyone download any Chemistry software to their TI-83 plus, if so which ones?

    Thanks

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