TBR Gen Chem Example 1.18

[750hp]

---

Members don't see this ad.

Hi everyone, was confused on where they got the "2" multiplier in order to arrive at C2H5 (before converting to the molecular formula). I got up to C1H2.5 but they for some reason multiplied it by 2 to get the final form of the empirical formula. Thanks in advance.

View attachment Untitled1.jpg

View attachment Untitled.jpg

 

[Erythropoietin]

Hi everyone, was confused on where they got the "2" multiplier in order to arrive at C2H5 (before converting to the molecular formula). I got up to C1H2.5 but they for some reason multiplied it by 2 to get the final form of the empirical formula. Thanks in advance.

View attachment 18072

View attachment 18073

you need to have whole numbers for an empirical formula

 

[750hp]

you need to have whole numbers for an empirical formula

Yeah, I realize that but, why didn't they just round 2.5 to 3? why did they choose 2 out of all numbers as the multiplier? Is it simply because 2 is the lowest number we can multiply by to give you a whole number?

 

[Erythropoietin]

Yeah, I realize that but, why didn't they just round 2.5 to 3? why did they choose 2 out of all numbers as the multiplier? Is it simply because 2 is the lowest number we can multiply by to give you a whole number?

You can't round an empirical formula
because C1H2.5 is different than C1H3

you can multiply 2.5 by 1.2 to give you 3, but since you multiply the whole thing, the formula now becomes C1.2H3 ....that still doesn't work

the closest number to round to a whole number is 2..so thats why C2H5 is the answer
you can even multiply it by 10 to give you C10H25 but that will still reduce to C2H5

So, something like: C3H4.5 (just made it up) will have an empirical formula of C6H9

 

[750hp]

You can't round an empirical formula
because C1H2.5 is different than C1H3

you can multiply 2.5 by 1.2 to give you 3, but since you multiply the whole thing, the formula now becomes C1.2H3 ....that still doesn't work

the closest number to round to a whole number is 2..so thats why C2H5 is the answer
you can even multiply it by 10 to give you C10H25 but that will still reduce to C2H5

So, something like: C3H4.5 (just made it up) will have an empirical formula of C6H9

Ah I see, that makes a lot of sense. Thanks a lot!