Question

I'm unsure about my answer for the Molecular and Empirical formula. Can H3PO2 be the empirical formula of H3PO4? And can C3H2 be the empirical formula of C3H8? Or am I not suppose to reduce it if the other subscript can't? If that makes any sense...

Answer 1

What is this? Physics?

Answer 2

No its Chemistry.

Answer 3

Sorry I'm still learning the basics, 9th grader. :(

Answer 4

Its okay. Thanks for at least looking at it! Its simply reducing so i think i'm over thinking it. Because the other problems were like this: P4O10 to P205

Answer 5

the answer is no inj both cases
the empirical fomula is the simplest formula which is found by analysis

eg the empirical formula of C2H4 is CH2

Answer 6

Oh I think I have a decent concept, might confuse you so nvm >.> Still ehh with it myself..

Answer 7

I know I'm over thinking it but cwrw238 the example you gave has two even subscripts. Mine don't. So does that matter or not? Does it go from C3H8 to C3H2? Is that right or do i leave it alone?

Answer 8

isnt there mols involved ?

Answer 9

Umm idk haha. My teacher gave us the molecular formula and we are suppose to write the empirical formula. Its like a chart

Answer 10

do you know the mass or the percent of each element ?

Answer 11

I could figure it out but will that help me find the empirical formula?

Answer 12

yes , im looking over my notes so i can help but what will you figure out ? the percent ?

Answer 13

I'll do anything to help you help me figure it out xD

Answer 14

haha ok ill try my hardest to explain , ik how to do it i just dont know what every step is called alright ?

Answer 15

okay lets say you know the percent of each element , ima do an example ok ?

Answer 16

Omg. I'm doing this too! But shouldn't u know some sort of weight of like the entire formula in order to find the empirical formula

Answer 17

Okay thats what i thought... I was getting confused but your sweet wednylisette!

Answer 18

92.26% carbon , 7.74 % hydrogen
carbons atomic mass = 12.01 hydrogens atomic mass = 1
so your going to divide the percent by its mass
carbon = \[\frac{ 92.26 }{ 12.01 }\]
hydrogen = \[\frac{ 7.74 }{ 1 }\]

Answer 19

you get it so far ?

Answer 20

Yeah but i don't get how it goes back to the Molecular and Empirical formula question i asked haha :)

Answer 21

just watch lol

Answer 22

okay after you divide them carbon = 7.681 and hydrogen = 7.74
this next part will tell you what subscripts your empirical formula will have

Answer 23

Okay.

Answer 24

your going to take the smallest number . 7.681 is smaller than 7.74 so you will divide BOTH numbers by the smallest number which is 7.681 .

Answer 25

carbon 7.681 / 7.681 = 1
hydrogen 7.74 / 7.681 = 1.007 which is basically 1

Answer 26

so carbon is 1 and hydrogen is 1
your empirical formula is now
C1H1 = CH

Answer 27

And thats for C3H8? Just making sure we're on the same page.

Answer 28

or that was just your example?

Answer 29

no thats an example . i can only figure it out if you give me the mols or the percent

Answer 30

but ok lets do C3H8
lets find the percent

Answer 31

alright. I'll do one and you do one. I'll do C3 and you do H8, is that okay?

Answer 32

you know how to get the percents ?

Answer 33

I'm looking haha. I did some earlier today but I don't think its the same way you did.

Answer 34

okay well find the atomic mass of each
C3 means theres 3 carbons so you will multiply the atomic mass by three ,
theres 8 hydrogens so you will multiply the atomic mass of hydrogen by 8.

Answer 35

C 12.01(3) = 36.03
H 1 ( 8 ) = 8

Answer 36

okay I got that far it was after that i didn't know.

Answer 37

now you just gotta find the percent so add those two numbers up
36.03
+ 8
= 44.03

Answer 38

and then you divide them both by 8?

Answer 39

now your gonna take the molar mass ( which is what we did in step one ) and divide it by the formula mass which is 44.03 ( the sum of both masses )

Answer 40

example with carbon . 36.03 / 44.03 = 0.8183
to turn that into a percent multiply it by 100
so now carbon is 81.83 %

Answer 41

Hydrogen 8/44.03 = 0.18169
x 100
= 18.169 which you can round to 18.17 %

Answer 42

ok... so I think I got it now. I think the answer is just stays the same. So its C3H8

Answer 43

now you gotta do the other part though , like what i did with my example

Answer 44

Okay thanks! I think i got it now :)

Answer 45

i hope so (:

Answer 46

Nice explanation @wendylisette what grade are you both in?

Answer 47

i'm in 10th although i'm the age to be in 11th... bad homeschooling got me behind XD

Answer 48

And yet years later i'm homeschooling again

Answer 49

10th