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Topic: Help with Theoretical Yield. I need help with this as soon as possible!  (Read 9761 times)

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Offline stag

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Here's the measurements from my expirement.
(reaction 1)
0.548 g Cu (s)
4.0 mL HNO3
100 mL DI water

(reaction 2)
30 mL 3.0 M NAOH

(reaction 3)
nothing was added.

(reaction 4)
200 mL of DI water
15 mL of 6.0 M HCl

(reaction 5)
2.095 g Zn
10 mL 6M HCl
5 mL methanol
5 mL DI water
40.767 g mass of evaporating dish
41.238 g mass of evaporating dish with solid

Here are the reactions:
reaction 1: theoretical mass of copper (II) nitrate formed
reactoin 2: theoretical mass of copper (II) hydroxide formed
reaction 3: theoretical mass of copper (II) oxide formed
reaction 4: theoretical mass of copper (II) sulfate formed
reaction 5: theoretical mass of copper formed

Offline opti384

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Re: Help with Theoretical Yield. I need help with this as soon as possible!
« Reply #1 on: February 23, 2011, 08:24:39 PM »
Why don't you first try to write the reaction equations for each?

Offline stag

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Re: Help with Theoretical Yield. I need help with this as soon as possible!
« Reply #2 on: February 23, 2011, 08:54:28 PM »
Here's the measurements from my expirement.
(reaction 1)
0.548 g Cu (s)
4.0 mL HNO3
100 mL DI water

(reaction 2)
30 mL 3.0 M NAOH

(reaction 3)
nothing was added.

(reaction 4)
200 mL of DI water
15 mL of 6.0 M HCl

(reaction 5)
2.095 g Zn
10 mL 6M HCl
5 mL methanol
5 mL DI water
40.767 g mass of evaporating dish
41.238 g mass of evaporating dish with solid

Here are the reactions:
reaction 1: theoretical mass of copper (II) nitrate formed
Cu+4HNO3-->Cu(NO3)2+2NO2+2H2O

reactoin 2: theoretical mass of copper (II) hydroxide formed
Cu(NO3)2+2NaOH-->Cu(OH)2+2NaNO3

reaction 3: theoretical mass of copper (II) oxide formed
Cu(OH)2-->CuO+H2O

reaction 4: theoretical mass of copper (II) sulfate formed
CuO+H2SO4-->CuSO4+H2O

reaction 5: theoretical mass of copper formed
Zn+CuSO4-->ZnSO4+Cu

Offline opti384

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Re: Help with Theoretical Yield. I need help with this as soon as possible!
« Reply #3 on: February 23, 2011, 09:13:15 PM »
Now that you have the equation, try to figure out the moles of Cu (s) and other reactants. The equation indicates in what ratio of amount the reactants react to create products.

In reaction 1, 1 mol of Cu reacts with 4 mols of HNO3 to create 1 mol of copper nitrate.

Offline stag

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Re: Help with Theoretical Yield. I need help with this as soon as possible!
« Reply #4 on: February 23, 2011, 10:36:26 PM »
okay, but which measurement do i use? my teacher said those measurements up there are also used in the calculations.

Offline rabolisk

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Re: Help with Theoretical Yield. I need help with this as soon as possible!
« Reply #5 on: February 23, 2011, 11:23:28 PM »
This is a series of reactions. The product from reaction 1 is the reactant for reaction 2, and so forth. You are missing the concentration of nitric acid in reaction 1 though...

Offline stag

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Re: Help with Theoretical Yield. I need help with this as soon as possible!
« Reply #6 on: February 23, 2011, 11:46:15 PM »
Could somebody show me how to do the first one because i am completely lost and my teacher is not helping me what-so-ever.

Offline rabolisk

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Re: Help with Theoretical Yield. I need help with this as soon as possible!
« Reply #7 on: February 23, 2011, 11:50:29 PM »
Do you understand the concept of theoretical yield?

Offline stag

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Re: Help with Theoretical Yield. I need help with this as soon as possible!
« Reply #8 on: February 24, 2011, 12:06:05 AM »
He only used one problem to show us how to do it in class and it was time to go so he didnt even leave it up there long enough for anybody to copy it. now he expects us to know how to do it.

Offline rabolisk

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Re: Help with Theoretical Yield. I need help with this as soon as possible!
« Reply #9 on: February 24, 2011, 12:13:25 AM »
Let's say I have a reaction:
A + 2B  :rarrow: 3C + D

That means for one molecule or atom or A will react with 2 of B to produce 3 of C and 1 of D. But if you have A with no B, or conversely, B with no A, then you won't get a reaction. This is the concept of limiting reactant. The reaction will proceed until you run out of A or B. So if I have 3 moles of A initially, and 4 moles of B initially, how many moles of C and D will you get eventually?

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