Take Home Exam- each person may post a maximum of 10 questions. I want you to do your own work, struggle a little, and ask questions only if absolutely necessary
Please post comments, questions in this section for the take home exam.
ur talking about number one right? wells..empirical means that the subscript is in its simplest form, so you look through the choices and simplify all of them. Choice A would be the answer because both of the compounds, when simplified, is CH. 2 and 2 simpify to one and 6 and 6 simplify to one also. Hope you find this helpful.
LJ: For number 2, the only choice that is in the simplest form is Choice (A). Choice (B) and (C) can both be simplified even more by dividing the coefficients by 2. You can divide the last one by 3. Choice (A) can not be simplified even more since if you divide both coefficients in the compound by 2, you'd end up with PO2.5 which is not possible. Hope this helped? o-o;;
for # 14 your putting it in mole to mole because their asking anout the molecular ratio and therefore Al2O3 is 2 moles of aluminim to 3 moles of oxygen
Lilly for number 15, i got A-1 mole of atoms. If you look at the other choice, they dont make sense. 10 grams of atoms would not be He, 3x10^23 atoms is wrong because its suppose to be 6.02x10^23, and the last one says liters and thats out of the question. "He" can represent 1 mole of atoms , since it has no other coefficienT.
For number 24 i got D First I did the math for each of them, I found the molecular mass FeSO3-136 FeSO4-152 Fe2(SO3)3-352 Fe2(SO4)3-400
Then you start with the first coumpound, the mass of Fe is 56, so 56/136= .41, we need it to be .28, for the second one its 56/152= .36, for the third, its 112/352= .31, and for the last one its 112/400 = .28, since the last one fits in so far, then you check it for all the elements, S- 32x3/400= .24 0- 16x12/400 = .48 Therefore D is the answer.
first you have to balance the equation which is as followed 5a=c,12a=2d,2b=2c+d. A=2,B=16,C=10,D=12. C5H12+8O2--5CO2+6H2O.then you do 5.0molO2 which is equal 18.01528gH2O/31.9988molO2. then 2.814993062gH2O= 1mol/18.01528gH2O which then equals .1562558596molH2O
Hey all, real quick question, are we supposed to do the short answer questions on a separate piece of paper or can we do it on the test? Or does it not really matter?
Need some help with 52. I'm almost certain I've balanced the equations, the coefficients I have are 1, 8, 5, and 6, respectively. I need to know if those are correct because I'm not 100% on them seeing as how when I try to solve it the answers aren't whole numbers. Thanks in advance!
Okay, so if it's correct then how would you change the coefficients so that there would be 5 moles of oxygen for number 52? I tried dividing each side by 1.6 since 8/1.6 = 5, but I'm not sure if that would lead to a correct answer (which, according to my work, is 6/1.6 = 3.75 mol of H20).
Also, while we're on the short answers, what did everyone get for 55c? I got 52.060 grams but I'm going to redo the entire problem because that doesn't seem right when applied to the other problems, specifically d. Anyone got a different answer?
which pair of compounds has the same empirical formula?
ReplyDeleteLJ:
ReplyDeleteur talking about number one right?
wells..empirical means that the subscript is in its simplest form, so you look through the choices and simplify all of them. Choice A would be the answer because both of the compounds, when simplified, is CH. 2 and 2 simpify to one and 6 and 6 simplify to one also.
Hope you find this helpful.
for #2 which is the empirical formula?
ReplyDeleteLJ: For number 2, the only choice that is in the simplest form is Choice (A). Choice (B) and (C) can both be simplified even more by dividing the coefficients by 2. You can divide the last one by 3. Choice (A) can not be simplified even more since if you divide both coefficients in the compound by 2, you'd end up with PO2.5 which is not possible. Hope this helped? o-o;;
ReplyDeletedid my last post count as help or just giving an answer..... o-o;;
ReplyDeletethanks
ReplyDeletewhat is the correctly represented by the formula H2SO4? for #14 do we put it in grams to grams or moles to moles?
ReplyDeletewow I should really start this...take home exam... ~.~ Uhmm I'll check it later when I finish my global work..
ReplyDelete[Useless post]
what is the correctly represented by the formula H2SO4? for #14 do we find it grams to grams or moles to moles?
ReplyDeletehow do you find the empirical formula of a compound that contains 28% iron,24%sulfur, and 48% oxygen by mass?
ReplyDeletethe formula H2O2 is what kind of example
ReplyDeleteI think H2O2 is a molecule..what do you mean by example?
ReplyDeleteyes that one
ReplyDeletefor # 14 your putting it in mole to mole because their asking anout the molecular ratio and therefore Al2O3 is
ReplyDelete2 moles of aluminim to 3 moles of oxygen
Did anyone balance the equation for number 38?i can't figure it out :[
ReplyDeletethe balanced equation would be:
ReplyDelete1Fe2O3+3CO -> 2Fe+3CO2
I just guessed and checked the numbers given and 3 worked.
lol, ok thanks ginger
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ReplyDeleteCan anybody help me with number 13?
ReplyDeleteThis comment has been removed by a blog administrator.
ReplyDeleteThis comment has been removed by a blog administrator.
ReplyDeletefor # 24 what is the empirical formula of a compound that contains 28%iron 24%sulfur 48%oxygen by mass?
ReplyDeleteThis comment has been removed by a blog administrator.
ReplyDeletefor number 15 which quantity can correctly be represented by the symbol He?
ReplyDeleteLilly for number 15, i got A-1 mole of atoms.
ReplyDeleteIf you look at the other choice, they dont make sense. 10 grams of atoms would not be He, 3x10^23 atoms is wrong because its suppose to be 6.02x10^23, and the last one says liters and thats out of the question. "He" can represent 1 mole of atoms , since it has no other coefficienT.
For number 24 i got D
ReplyDeleteFirst I did the math for each of them, I found the molecular mass
FeSO3-136
FeSO4-152
Fe2(SO3)3-352
Fe2(SO4)3-400
Then you start with the first coumpound, the mass of Fe is 56, so 56/136= .41, we need it to be .28, for the second one its 56/152= .36, for the third, its 112/352= .31, and for the last one its 112/400 = .28, since the last one fits in so far, then you check it for all the elements, S- 32x3/400= .24 0- 16x12/400 = .48
Therefore D is the answer.
For number 55, what did u guys get for the limitting and exess reactants?
ReplyDeleteFor 55, Chlorine is the excess. Phosphrus is the limit.
ReplyDeleteI tried it again, and I got the opposite, I got Cl2 is the limiting and P4 is the excess. im not sure now lol
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ReplyDeleteThis comment has been removed by the author.
ReplyDeleteI need help with number 52
ReplyDeletefirst you have to balance the equation which is as followed 5a=c,12a=2d,2b=2c+d. A=2,B=16,C=10,D=12. C5H12+8O2--5CO2+6H2O.then you do 5.0molO2 which is equal 18.01528gH2O/31.9988molO2. then 2.814993062gH2O= 1mol/18.01528gH2O which then equals .1562558596molH2O
ReplyDeletefor #42 all you have to do is multiply 1.5 and 5 right? cause im not sure
ReplyDeletei am confused on #13. i got B is that right
ReplyDeleteYes
ReplyDeleteHey all, real quick question, are we supposed to do the short answer questions on a separate piece of paper or can we do it on the test? Or does it not really matter?
ReplyDeletewe answer the short answers on a separate piece of paper.
ReplyDeleteNeed some help with 52. I'm almost certain I've balanced the equations, the coefficients I have are 1, 8, 5, and 6, respectively. I need to know if those are correct because I'm not 100% on them seeing as how when I try to solve it the answers aren't whole numbers. Thanks in advance!
ReplyDeletei need some help with #55 for the equation i got Cl2+P4= P5Cl
ReplyDeleteBorana
ReplyDeleteyou are right the limiting is Cl the excess is P i was confuse myself on that one but when i did it a few time it still came out to be that
Nils,
ReplyDeleteYou've balanced it correctly. There are 5 carbons, 12 hydrogens, and 16 oxygens on each side.
Okay, so if it's correct then how would you change the coefficients so that there would be 5 moles of oxygen for number 52? I tried dividing each side by 1.6 since 8/1.6 = 5, but I'm not sure if that would lead to a correct answer (which, according to my work, is 6/1.6 = 3.75 mol of H20).
ReplyDeleteAlso, while we're on the short answers, what did everyone get for 55c? I got 52.060 grams but I'm going to redo the entire problem because that doesn't seem right when applied to the other problems, specifically d. Anyone got a different answer?
Just re-did my calculations and ended up with 38.658, which seems a lot better. Anyone get something similar?
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ReplyDeleteGUYS! Is phosphorus pentachloride P4Cl5?
ReplyDeleteyes jamie P4cl5 is phosphorus pentachloride
ReplyDeleteOh, WOW. I completely forgot that it was P4Cl5, I was just doing PCl5. Thanks guys!
ReplyDelete