S.o.s.

[finaltomorow]

if anyone could answer some of these questions and possibly explain how to do one or two that would be awesome and i owe you my life. and if anyone can explain it break it down as much as possible please.

1.tina adds 217 g of iron(III) carbonate to a beaker containing HCl. Calculate the mass of Iron(III) chloride and the mass of water that are produced in the reaction.

theres one

2.louisa wants to fill a large balloon with a carbon dioxide that is produced by this reaction. What mass of hydrochloric acid will she have to use in order to produce a volume of 100. L of C02 at STP?

3. How many molecules of iron(III) carbonate does tina need to react with 5.0 x 10to25 formula units of HCl? What is the mass of this quantity of iron(III) carbonate?

[Monique]

Take a look at this thread and memorize the tip that is in the last post!
http://www.physicsforums.com/showthread.php?s=&threadid=11790

Always first write down the equation and make sure it is balanced: that there are the same amounts of each element on each side of the equation. You also need to calculate the molecular weight (mw) of the molecule you are calculating with.

If you want to check your progress, post your answer here and I can tell you if you're on the right track :)

[Monique]

I'll just repost the tip:
I always have the following picture in my mind:


* mw * 6.022 x 10^23
grams <-- moles --> molecules

|
|* 22.4L (at STP)
V

liters It is all very simple, just remember that picture and the fact that you ALWAYS have to multiply when you go from the mole to any of the other measurements. And when you want to convert something into a mole, you ALWAYS divide.

[finaltomorow]

1.tina adds 217 g of iron(III) carbonate to a beaker containing HCl. Calculate the mass of Iron(III) chloride and the mass of water that are produced in the reaction.

[Monique]

Sorry, but you have to show a little thinking on your side first.. what exactly are you having problems with?

Write the reaction equation
Balance it
Calculate mw of iron(III)carbonate, iron(III)chloride, water
Do the calculation as described by the tip

[Monique]

Oh, so the objective is the convert grams into moles (here you can adjust for reaction ratios) and back into grams.

[thunderfvck]

Fe2(CO3)3 + HCl ---> FeCl3 + H2O

How do you balance for the carbon if there's no carbon as a product. CO2?

oh yeah. H+ + carbonate makes CO2!

Fe2(CO3)3 + 6HCl ---> 2FeCl3 + 3H2O + 3CO2

now you just put your grams into moles using moles = grams/(molar mass) and multiply by the coefficient in FeCl3 and H2O.

[Monique]

Yes, CO2.. hydrocarbonate is the intermediate: H2CO3 (which is a very unstable compound, additive in soda/pop) which desintigrates into H2O and CO2

[Monique]

Originally posted by thunderfvck
Fe2(CO3)3 + 6HCl ---> 2FeCl3 + 3H2O + 3CO2 Do you see how that equation was balanced, finaltomorrow?

[finaltomorow]

you see im not very good at balancing the equations etc. i dont know the first step in most of these things. i can convert moles into grams and thats about it. i dont know what the signifigance of Fe(III) is and what you have to do to change it to liters. also when the reaction happens does some of one of them go away? i dont know honestly.

[Monique]

Fe 3+ (III means charge of three)
CO3 2-

Thus iron(III)carbonate is Fe2(CO3)3

[thunderfvck]

I hope Monique isn't answering while I'm typing. :)

Okay, so. Into liters? Not too hard! I'm sure you remember those beloved gas laws, specifically PV=nRT. I hope you know what those variables represent. So, at STP you have 101.3 kPa as a pressure, 273 K (I THINK) for temperature, R is something like 8.301 opr whatever (I really am not too sure on that one, it's been awhile). AND you want 100 L of gas, so you got all your variables and you can solve for n (number of moles). So n=(PV)/(RT). And then you will see how many moles of gas you would need to occupy 100 L of space at STP. So now you've got this number, so then you multiply that by 2 and you'll get the number of moles of HCl required. Because in the balanced equation you have 3 CO2's formed when 6 HCl's reacted with blah. So that tells you that the proportion of CO2 formed to HCl used up is 3:6, or 1:2, so that's why you mulitply by two.
Balancing equations is really easy. Just make sure you have the same number of a particular element on each side. eg. 2H2 + O2 --> 2H2O. Notice how there are 2 oxygens on the right, and on the left. And that there are 4 hydrogens on the left and right? This is balanced. It takes a bit of practise but it's easy.
AND Fe(III) means that this metal has an oxidation state of +3. That means, for example, you would need three chlorines (all of which have a -1 oxidation state) to balance the +3 on Fe(III). FeCl3.
Hope I helped.

[Monique]

I have to catch my train, good luck, someone else might help you along further :)

[finaltomorow]

ok so if you add up the product you get 247.5 i think??? something like 1,498.95 when you multiply by 6.02 .?

[thunderfvck]

sorry, but what calculations are you doing?

[finaltomorow]

thank you both for trying to help. its midnight and i need to try to get this done along with my project. btw this is normal high school chem and very confusing for me lol.

[finaltomorow]

maybe ill stay up a while longer than lol. i dont know what im doing trying to get an answer

[finaltomorow]

or trying to understand it more of

[thunderfvck]

you poor soul. what exactly is troubling you? what don't you understand?

[finaltomorow]

goodnight all and thanks

[Monique]

Good luck :) next time stop by earlier, we could've helped you more :S :)

[finaltomorow]

yea i found this site too late but i know where to come next time

[GCT]

Yeah, it is not a good idea to procrastinate on chemistry. In case you are still interested (you should be interested if you are a science major)...


1.tina adds 217 g of iron(III) carbonate to a beaker containing HCl. Calculate the mass of Iron(III) chloride and the mass of water that are produced in the reaction.

Whenever you are to use a balanced equation you will always end up using moles or rather the molar equivalence of the reaction.

So first things first...covert grams to mole. Here is the balanced equation.

assuming you have excess HCl (which we do in this case)

Fe2(CO3)3 + 6HCl ---> 2FeCl3 + 3H20 + 3CO2

moles of iron(III) carbonate(3 moles of water/1 moles of iron(III)carbonate)=moles of water formed...covert to grams.

Try this for Iron (III) chloride.

2.louisa wants to fill a large balloon with a carbon dioxide that is produced by this reaction. What mass of hydrochloric acid will she have to use in order to produce a volume of 100. L of C02 at STP?

At STP 1 mole/22.4 L. That is one mole of gas occupies 22.4 L. Figure out how much moles will be in a volume of 100L.

Again use the equation. This time we are working backwords nevertheless it should be not be a problem. We are assuming that we have Fe2(CO3)3 in excess.



3. How many molecules of iron(III) carbonate does tina need to react with 5.0 x 10to25 formula units of HCl? What is the mass of this quantity of iron(III) carbonate?

This question deals with the topic of limiting reagent. Remember one mole of any compound = 6.022 x 10^23 units.

Again, we will need to convert to moles. Simply divide the formula units in the problem by 6.022...and you have the number of moles. Work backwards and figure out how many moles of iron(III) carbonate are needed. Multiply this quantity by 6.022...To find the mass multiply the number of moles times molar mass.

[finaltomorow]

science isnt my strongpoint but i passed it today. it was close but oh well. i really dont think i could of done it without you guys help.