# How do i do this?

#### ManBearPig

##### Diamond Member
How many moles of Mn atoms are there in 116.0014 grams of KMnO4?

I seriously have no idea.

#### pontifex

##### Lifer
Originally posted by: Heen05
How many moles of Mn atoms are there in 116.0014 grams of KMnO4?

I seriously have no idea.

#### Encryptic

##### Diamond Member
Sounds like someone should be cracking the books more often, or the only moles you'll have to worry about are the ones in the lawn you're mowing for minimum wage.

#### FoBoT

##### No Lifer
you need to know how many atoms per mole
or how many moles per gram
or something

good question

#### Gunslinger08

##### Lifer
0.7340002531004808909136927360162

#### 2Xtreme21

##### Diamond Member
6.02x10^23

The only thing I got out of highschool chemistry.

#### Brainonska511

##### Lifer
Find out the mass of 1 mole of KMnO4.

Then convert: your mass of KMnO4/actual mass * 1 mole of Mn/1 mole of KMnO4 = moles of Mn in KMnO4.

A ridiculously easy problem and if you couldn't figure this out, you are in a lot of trouble when it comes to the harder stuff.

#### dullard

##### Elite Member
(2) Find out the mass of one KMnO4 molecule.
(3) Findout how many molecules you have (divide the mass of all of them by the mass for one).
(4) You know how many molecules you have, so you know how many Mn atoms you have.
(5) A mole is like a dozen. 12 eggs = 1 dozen eggs. Same concept. Except you use a bigger number than 12. Convert into moles.
(6) Drop out of chemistry as you clearly aren't going to do well at all.

42

#### ManBearPig

##### Diamond Member
thanks a lot guys...if you don't wanna answer you don't have to. appreciate it though.

im just trying to get down how to do it, not exactly what the answer is.

any takers for how to go from atoms to milligrams?

thanks

#### Vegitto

##### Diamond Member
You go from atoms --> moles --> grams --> milligrams .

#### Gunslinger08

##### Lifer
These people are mostly wrong.

You find the molecular weight of the compound and divide the given number by this. This gives you the number of moles of each element in the compound.

But, I haven't taken chemistry in the past 5 years, so don't take my word for it.

#### Al Neri

##### Diamond Member
Originally posted by: j00fek
good question

good troll to get your postcount up

#### dullard

##### Elite Member
Originally posted by: Heen05
thanks a lot guys...if you don't wanna answer you don't have to. appreciate it though.
Ok, we'll step you through it. Heck, I'll combine some of my steps to make it even simplier.

Look here for a periodic table of the elements. Click on K. You get the atomic weight here. Unfortunately that website failed chemistry and forgot to use units, but it is 39.098 g / mole of K.

Repeat for Mn and O. You'll get 54.9390 g /mole of Mn and 15.9994 g /mole of O.

In your molecule you have 1 K atom, 1 Mn atom, and 4 O atoms. Thus, a mole of KMnO4 would weigh: 39.098 g + 54.9390 g + 4*15.9994 g = 158.0346 g of KMnO4.

You have 116.0014 g of KMnO4. Thus you have (116.0014 g of KMnO4) / (158.0346 g / mol of KMnO4) = 0.7340253 mol of KMnO4.

You have 1 mole of Mn per mole of KMnO4 because there is one atom of Mn per molecule of KMnO4. Thus you have 0.7340253 mol of Mn.

Really, this is as easy as chemistry can possibly get. Add 3 numbers and divide once. If you are struggling on this for a class, then you really need to hire a tutor. If you are doing this for some other reason, then you really aren't the right person to be doing it, and you should find someone else to do the task.

#### Gunslinger08

##### Lifer
Originally posted by: dullard
Originally posted by: Heen05
thanks a lot guys...if you don't wanna answer you don't have to. appreciate it though.
Ok, we'll step you through it. Heck, I'll combine some of my steps to make it even simplier.

Look here for a periodic table of the elements. Click on K. You get the atomic weight here. Unfortunately that website failed chemistry and forgot to use units, but it is 39.098 g / mole of K.

Repeat for Mn and O. You'll get 54.9390 g /mole of Mn and 15.9994 g /mole of O.

In your molecule you have 1 K atom, 1 Mn atom, and 4 O atoms. Thus, a mole of KMnO4 would weigh: 39.098 g + 54.9390 g + 4*15.9994 g = 158.0346 g of KMnO4.

You have 116.0014 g of KMnO4. Thus you have (116.0014 g of KMnO4) / (158.0346 g / mol of KMnO4) = 0.7340253 mol of KMnO4.

You have 1 mole of Mn per mole of KMnO4 because there is one atom of Mn per molecule of KMnO4. Thus you have 0.7340253 mol of Mn.

Really, this is as easy as chemistry can possibly get. Add 3 numbers and divide once. If you are struggling on this for a class, then you really need to hire a tutor. If you are doing this for some other reason, then you really aren't the right person to be doing it, and you should find someone else to do the task.

Originally posted by: joshsquall
0.7340002531004808909136927360162

#### dullard

##### Elite Member
Originally posted by: joshsquall
Originally posted by: joshsquall
0.7340002531004808909136927360162
He never asked for the answer, only how to do it. But you did the math close to correctly. You only forgot the units and your sig figs are way out of whack.

#### Gunslinger08

##### Lifer
Originally posted by: dullard
Originally posted by: joshsquall
Originally posted by: joshsquall
0.7340002531004808909136927360162
He never asked for the answer, only how to do it. But you did the math close to correctly. You only forgot the units and your sig figs are way out of whack.

Just wanted to ensure that everyone knows I'm the smartest man alive.

BTW, boo for sig figs.