A compound contains only carbon, hydrogen and oxygen.?

Question

Combustion of 10.68 mg of the compound yields 16.01 mg CO2 and 4.37 mg H2O. The molar mass of the compound is 176.1 g/mole. What are the empirical and molecular formulas of the compound

Answer 1

lets see CxHyOz + O2 >>> CO2 + H2O right?
molar mass of CO2 is 12 + 16+ 16 = 44
molar mass of H2O is 1+1+16=18
no. of moles of CO2 is 16.01/44= 0.000364 mols
no. of moles of H2O is 4.37/18= 0.000243 mols
no. of moles of CxHyOz is 10.68/176.1=0.0000606
CO2:H2O:CxHyOz
0.000364:0.000243:0.0000606
about 6 : 4 : 1
so lets balance the equation using the ratio to find the empirical formular (smallest)
CxHyOz + O2 >>> H20 + CO2
CxHyOz + O2 >>> 4H20 + 6CO2
so we know that x=6,y=8
From this C6H8 we know molar mass is 80.
To get 176 just Times 2 and add an oxygen.
C12H16O this is the empirical formular
molecular fomular is simple since there is one oxygen it is an alcohol. C12H15OH
a double benzene ring with 2 double carbon bonds
tada!!

Answer 2

To get ratio for C and H from data: first determine mass of carbon and hydrogen which came from the sample and divide by atomic wt to get atomic ratio.

16.01 x 12/44 = 4.366mg (4.366/12 = 0.369)

4.37 x 2/18 = 0.486mg (0.486/1 = 0.486)

Now find out the weight of oxygen in the sample from difference:

10.68mg "CHO" -4.366mg"C" - 0.486mg"H" = 5.83mg"O"

Note this value is already mg oxygen (not water or CO2 etc)so we only need to divide by 16 to get atomic ratio.

5.83 x 1/16 = 0.364

now find the smallest whole numbers for your ratio of:

C 0.369; H 0.486; O 0.364

Ratio = C3H4O3 = 88amu; divide it into the known molecular weight to see if it comes out evenly 176.1/88 = 2.001, so formula is C6H8O6

Answer 3

CxHyOz + O2 ---> CO2 + H2O moles CO2 = 2.2/40 4 = 0.05 moles H2O = a million.2/18 = 0.067 total # ratio = 3CO2 + 4H2O thus, for molar mass of ~ 60, you have C3H8O and stability equation would appear as if 2C3H8O + 9O2 ---> 6CO2 + 8H20 and the moles paintings out so 1g = 0.016 mole ---> 0.05 moles + 0.067 moles

Answer 4

The answer is very easy.but one has to sit and work.Why do you expect others to do your homework?

Answer 5

wow...who woud sit and fig. that out? do it yourself...the formulas are'nt too complicated