any chem fags out there trying to help me with some problems

Drunk chem fag here.

Show me what you've got.

>>>>>>/sciences/

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>>536452397
The problems, not the set. I've seen the set before.

>>536452541
1st Ca3(PO4)2+H2SO4->CaSO4+H3PO4
suppose the reaction is carried out starting with 103g of ca3po42 and 75g h2so4.

which substance is the limiting reactant? how many grams of the excess reactant will remain? what is the max amount of H3PO4 produced? and what is the percent yield if you obtain 40g of CaSO4?

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bump

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2nd The combustion of liquid ethanol, C2H5OH, produces carbon dioxide and water, after 4.64 mL of ethanol (density=0.789g/mL) was allowed to burn in the presence of 15.75g of oxygen, 3.72mL of water(density=1.00g/mL) was collected

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>>536453441
What is the oxidizer? what is the reducing agent?

Balance the reaction using the half reaction method to provide the net ionic equation.

what is the percent yield of water?

which reactant remains in excess and how much, in mg, remains?

very high chemfag here:

>you just have to turn the masses into moles for most of these questions and then do subtraction

>>536452961
Divide the weight of calcium phosphate and sulfuric acid by their molar masses to find molar equivalents. The one with less moles is the limiting reagent.

Subtract the moles of limiting reagent from moles of excess reagent, then convert back to grams by multiplying by it's molar mass, that's your excess.

Moles of excess reagent is equal to the moles of maximum amount of either product, convert back to grams by molar mass or leave the answer in moles.

Subtract the moles of calcium sulfate from the moles of the limiting reagent, divide by moles of limiting reagent, multiply by 100% to find percent yield.

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>>536454296
How high? What does your lab do?

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>>536454448
thank you, if you like to check my answers i got
1.H2SO4 is limiting
2.15.97g of Ca3(PO4)2 remain in excess
3.max amount of phosphoric acid produced is 55.01 g or .5613mols
4. 52.3% of CaSO4 is the precent yield if you obtain 40g of CaSO4

>>536453441
>>536452961
i remember gen chem... i also remember when i thought that stuff was hard.

then i took ochem. and quant. next year is pchem, instrumental, and lots of math electives for my minor.

almost done!

>>536455107
I generally learn based on how well the teacher teaches, and my teacher uses 30mins of class bitching and eating her breakfast.

>>536453732
Your reactants are ethanol and oxygen. What the fuck do you think is the oxidizer? The reducing agent is the one that isn't the oxidizer.

I don't know how to explain how to do this. Write the equation down and start trying combinations of co2 and h2o and check if they add up to the same number of C O H atoms as whole numbers of ethanol and oxygen.

This part is a lot of unit conversions. Learn how to do this or you'll just fail later. I'm not going to solve it for you.

You should be able to figure this out from the answer to the last question. Subtract the moles of excess reagent from the moles of limiting reagent. Convert back to grams.

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>>536455718
I've done the problem already I'm just not confident in my answers
1.the oxidizers o2 the reducing agent is C2H5OH
2. 86.7% water
3. 8122.9mg remains of O2

>>536455508
get used to failing. i've found most teachers to be almost completely useless on the podium. the best ones generally only teach a class i want one term of the year and the rest is disinterested jackasses.

learn to learn on your own. and always check out your professor's office hours. that's how you get ahead.

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>>536455508

yea you can't use that excuse at all otherwise you are fucked and are going to be homeless.

You need to learn to learn by yourself all my teachers suck.

oh and op here is the work for balancing.

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>>536456186

Stay out of my territory.

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>>536457201
getting my shit together slowly addictions a bitch, but hey I got the same answer cheers.

>>536457823
I got green meth coming off the line soon give it up gramps

>>536455039
1. Right.
2. I got ~24g. Bear in mind I'm drunk, though.
3. I got ~50g. Bear in mind I'm drunk, though.
4. I got ~62%. Bear in mind...

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>>536458414

>implying a cook using Scope will be 99% pure

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>>536459060
see picture.

Any chemfags notice some of the shit in breaking bad that kinda made them say "that's not quite rite, m8."? Like how they pronounce "methylamine" weird? Or how walt gets an enantomerically pure product using raw chemicals, whereas making meth from pseudoephedrine (what he did at first) would yield enantomerically pure meth given that the pseudoephedrine was enantomerically pure in the first place?

>>536458934
2. i did .3321mols Ca3 - .2806 mols Ca3(H2 Converted) then multiplied by 310.17g(Ca3(PO4)2 molar mass)

>>536460895
Where did you get those molar amounts? I have 0.996 moles Ca(PO4)2 and 0.765 moles sulfuric acid.

I did 103g calcium phosphate - [ 75g h2so4 -> convert to moles h2so4 -> (1mole Ca(PO4)2 / 3moles h2so4) -> convert to grams Ca(PO4)2 ] = ~24g

>>536463575
molar for Ca3(PO4)2 not Ca(PO4)2 and i had the wrong molar mass for sulfuric acid with the corrections I got 23.94G excess

>>536463575
with the correction for sulfuric acid I also ended up with 49.69g for #3 and 57.6% for#4