Question

An unknown compound contains only carbon, hydrogen, and oxygen (). Combustion of 7.50 of this compound produced 11.0 of carbon dioxide and 4.50 of water.

1) How many moles of carbon, C, were in the original sample?
An unknown compound contains only carbon, hydrogen, and oxygen (). Combustion of 7.50 of this compound produced 11.0 of carbon dioxide and 4.50 of water.

1) How many moles of carbon, C, were in the original sample?

Answer 1

Givern:

n(C)=m/M m(CO2)=11.0 M(CO2)=44.01

n=11/44.01 =0.249943194moles = moles of Carbon If you wanted to find the empirical formula though,

Solve for the empirical formula of CH2O

n(H)=4.5/18.016 =0.249777975x2= 0.49955595moles of H

m(H)= 0.499556x1.008=0.50355

m(C)= 0.2499x12.01= 3.0018 7.50-0.50355-3.0018 = 3.99g = 0.24966moles of O

C =0.2499/0.2497 =1

H = 0.4996/0.2497 =2 0

0.2497/0.2497

1 therefore the empirical formula=CH2O