http://oi68.tinypic.com/sfv70p.jpg
Well first off looking at the diagram we can see the reactants and the products. From this we need to make an equation. In the diagram it is helpful that each element has a key. From this we can work out how many of each element/compound there are. In the first box we see: 2 lots of NH3 and also two lots of CIF3. In the second box we see: 1 lot of N2, 1 lot of Cl2 and 6 lots of HF. Now we can make an equation: 2 NH3 + 2 ClF3 = N2 + Cl2 + 6 HF Lets do the rest in steps: 1. Now to work out grams of an element we first need to work out the moles. The equation for this is: mass/molar mass You can use either one of the masses (g) you have and molar mass is the mass of NH3 or CIF3 (add all the relative atomic masses together from periodic table) 2. Once you have done this, you will have the moles for either NH3 or CIF3 (which ever one you chose). You then need to deduce the moles (work out the moles for the products you're trying to find the mass for). Because the moles of whatever you worked out is x2 (because in the equation there are 2 lots of NH3 and CIF3), you will need to half the answer you got by 2 to get the moles for N2 and Cl2 (because there is only 1 lot of both of those in the equation). Then, to get the moles for HF, you will need to times the answer by 3, because there are 6 lots of HF's in the equation, and the answer you have is for 2 moles. 3. Once you have done that for each product (N2, Cl2 and HF), you can then work out the mass in grams for all of them. To do this you use this equation: molar mass x moles You take the moles of each product (that you worked out earlier) and times it, by each products molar mass. For example, the molar mass for HF would be hydrogen's relative atomic mass (on periodic table) add fluorine's relative atomic mass. Do that for each product, and then you will end up with the answer in grams, for each one. 4. To check you were write, you can add the grams of the reactants at the beginning together to get a total number, and then in a separate calculation, add the mass in grams of all of the products together. The numbers should be the same (due to the law of conservation of mass). I hope this can help, and I hope you can work it out! If you have any problems, feel free to message me. :)
@matt101
I agree with exactly what @jebonna said. Follow those steps carefully and you'll get the answer!
I'm getting confused with what they are saying though.
@matt101
What don't you understand?
What exactly I'm need to set up and what goes where. I need to see that visually I think.
I tried to set up a problem a little bit
|dw:1446925608633:dw|
|dw:1446925892849:dw|
Is that done right?
Ok let's start from the beginning. Here's the basic outline of what needs to happen (paraphrasing what was written above) - let me know if this isn't clear: STEP 1: Come up with a chemical reaction. This will let us figure out how many products we should expect based on the reactants used. STEP 2: Find moles of each reactant (remember, we can't figure out amounts using masses), and determine the limiting reactant (since we're given masses of both starting reactants). STEP 3: Calculate the moles of each product you should get based using stoichiometry and the chemical reaction you came up with in step 1. STEP 4: Convert the moles of each product back to masses. Start with step 1. What is your reaction?
2 NH3 + 2 ClF3 = N2 + Cl2 + 6 HF
Was what I put above in the drawing remotely right?
Sorry you posted just as I did! Let me have a look
It's fine.
Ok what you did is close, but you're going to want to divide by 2 (the stoichiometric coefficient) rather than multiply by 2 to determine which is the limiting reactant. However, the number you get before dividing by 2 are the ACTUAL moles of each reactant you're working with, and these are the numbers you will use to calculate the moles of each product.
|dw:1446926447363:dw|
So would it be like that instead. Obviously with a different answer.
You still need to divide by 2. I get that you divided what you HAD by 2, but what I meant was that you need to divide originally INSTEAD of multiply. And yes with different answers.
Is the 2 coming from the chemical equation?
Yes!
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Right and after you do the same for the other reactant, which is the limiting reactant?
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