A couple of questions... AS Chemistry

I was given a mass spectrum and asked to work out the relative molecular mass of X giving a reason for my choice. Following the diagram I got this:
((15 x 30) + (29 x 40) + (43 x 90) + (58 x 10)) ÷ 100 = 60.6
It then says, "Hence show that the molecular formula of X is C4H10" and now I'm confused since C4H10 would equal 58? Where have I gone wrong?

------------------------------------------------------

Complete combustion of X in oxygen gives carbon dioxide and water only.
i) Write an equation for this combustion reaction
2 C4H10 + 13 O2 --> 10 H2O + 8 CO2

ii) Calculate the total volume of the gaseous mixture produced when 2cm3 of gaseous C4H10 is mixed with 15cm3 of oxygen and completely burned. All volumes are measured at room temperature and pressure.

Any help would be great (: I'm not sure where to begin with the second one? Thanks a lot

Reply 1

EierVonSatan

21

First question, you're overcomplicated it :tongue:

the largest mass/charge ratio corresponds to the molecular ion - so in this case 58 :smile:

Second question, you need to look at the ratio of compounds in the chemical equation - you start with 15cm³ of gas (moles are directly proportional to volume with gases), H2O is a liquid at room temperature so all the gas afterwards is just the CO2 15cm³ ---> 8cm³ :smile:

Reply 2

username225218

OP

8

EierVonSatan

First question, you're overcomplicated it :tongue:

the largest mass/charge ratio corresponds to the molecular ion - so in this case 58 :smile:

Second question, you need to look at the ratio of compounds in the chemical equation - you start with 15cm³ of gas (moles are directly proportional to volume with gases), H2O is a liquid at room temperature so all the gas afterwards is just the CO2 15cm³ ---> 8cm³ :smile:

Thank you so much for your help (: That makes far more sense xD

A couple of questions... AS Chemistry

Related discussions

Latest

Trending

Trending

Articles for you