i need some help on chemistry homework..

ember said:
yeah but thats when you are comparing products with reactants in your problem you are comparing reactants or at least that first one anyway
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ah okay. agh this is a killer homework haha. I tried to get this homework done before i left for practice. but it took me forever to try and answer the questions and got stuck on these questions.
 
coolgirlspyer90 said:
ah okay. agh this is a killer homework haha. I tried to get this homework done before i left for practice. but it took me forever to try and answer the questions and got stuck on these questions.
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Yeah it used to take me HOURS to get my homework done and I mean HOURS but I kept at it and practice makes perfect but you do need to understand the concepts. What I can tell you is that for example your "railroad track" or so I call it will start with the 7.0 mil C2H6 and you have to make valid relationships along the way that will get you to the amount you want. I will look something like this

7.0 mol C2H6/ mol CO2
mol C2H6

the problem is since its mol to mol and reactants only I don't remember the next step but thats basically what your notes are telling you to do grams to mol and mol to gram are so much easier...

Here is one tip think of it as an hour glass you convert everything to to mol and then back out to what you need

make sense
 
ember said:
Yeah it used to take me HOURS to get my homework done and I mean HOURS but I kept at it and practice makes perfect but you do need to understand the concepts. What I can tell you is that for example your "railroad track" or so I call it will start with the 7.0 mil C2H6 and you have to make valid relationships along the way that will get you to the amount you want. I will look something like this

7.0 mol C2H6/ mol CO2
mol C2H6

the problem is since its mol to mol and reactants only I don't remember the next step but thats basically what your notes are telling you to do grams to mol and mol to gram are so much easier...

Here is one tip think of it as an hour glass you convert everything to to mol and then back out to what you need

make sense
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ah i think so. Here's what i've been doing so far on one of these problems (and hopefully got it right)

How many grams equal 1.0 mol of Azurite, Cu3(CO3)2(OH)2?<- my teacher told me to add the numbers from the element, and multiply the number next to the element. So that's how i got 340.7G

My answer: ?G=1.0 mol X 340.7G/ 1 mol= 340.7 G

I crossed off the mol while doing this problem
 
5) A mole of carbon and a mole of hydrogen have different masses, but both represent 1.00 mol of substance. explain.

If you look at the periodic table, you see the atomic mass for each element, right?

Carbon = 12.011 grams = 1 mol Carbon
Hydrogen = 1.0079 grams = 1 mol Hydrogen

I think Avogadro's number is used here to make the units same to make comparison easier--all in mol

Arrgghhh, chemistry sucks. I'm not usually great with chemistry as I prefer physics and math over chemistry. Haha.
 
coolgirlspyer90 said:
ah i think so. Here's what i've been doing so far on one of these problems (and hopefully got it right)

How many grams equal 1.0 mol of Azurite, Cu3(CO3)2(OH)2?<- my teacher told me to add the numbers from the element, and multiply the number next to the element. So that's how i got 340.7G

My answer: ?G=1.0 mol X 340.7G/ 1 mol= 340.7 G

I crossed off the mol while doing this problem
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break each element down and show me what you did I got a different number
 
sheila022 said:
5) A mole of carbon and a mole of hydrogen have different masses, but both represent 1.00 mol of substance. explain.

If you look at the periodic table, you see the atomic mass for each element, right?

Carbon = 12.011 grams = 1 mol Carbon
Hydrogen = 1.0079 grams = 1 mol Hydrogen
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OHHHHHH i get it. wow i didn't notice that. :Oops::doh:
 
For number 4,

Just count how many atoms are there for each element on both sides. If the numbers come out different, then it's not balanced. let me know if you have issues with number 4.
 
ember said:
break each element down and show me what you did I got a different number
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Cu3- 63.54X3=190.62
(CO3)2:
Carbon: 12.01X 3=36.03
Oxygen-16.00X3=48
then i added 36.03+48X2=132.03
O- 16.00
H-1.01
Added 16.00+1.01X 2= 16.16

then i added all together which i got 338.81, my interpreter told me to round up, so i got 340.7G
 
coolgirlspyer90 said:
Cu3- 63.54X3=190.62
(CO3)2:
Carbon: 12.01X 3=36.03
Oxygen-16.00X3=48
then i added 36.03+48X2=132.03
O- 16.00
H-1.01
Added 16.00+1.01X 2= 16.16

then i added all together which i got 338.81, my interpreter told me to round up, so i got 340.7G
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in CO3 the 3 is only applicable to the O and in the original problem you had (OH)2 is it one or two
 
sheila022 said:
For number 4,

Just count how many atoms are there for each element on both sides. If the numbers come out different, then it's not balanced. let me know if you have issues with number 4.
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so its basically asking to balance it. like how you would normally do for a balancing equation problem? something like this? --

___Al+ ___F2---> ____AlF3

my answer:

2 Al + 3 F2---> 2 AlF3
 
sheila022 said:
Yep! that's right!
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haha okay.. so the only part thats confusing me on the question number 5 is the elements with the 2 lines besides it to try and balance out the equation. I'm not sure why he put that there.

what i'm thinking is:

Rb+ RbNO3---> Rb2+N2

2 Rb 3?

Nothing for N

and nothing for O?
 
coolgirlspyer90 said:
haha okay.. so the only part thats confusing me on the question number 5 is the elements with the 2 lines besides it to try and balance out the equation. I'm not sure why he put that there.

what i'm thinking is:

Rb+ RbNO3---> Rb2+N2

2 Rb 3?

Nothing for N

and nothing for O?
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something is wrong here where is the O on the product side
 
coolgirlspyer90 said:
oops thanks for pointing that out.

Rb+ RbNO3---> Rb2O+N2

2 Rb 3?

Nothing for N

and nothing for O?
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no thats not right your products and reactants have to match so if you have 3 O on the reactant side how do you make that match the product side
 
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