Question

An unknown compound contans only C, H, and O. Combustion of 5.70 g of this compound produced 11.4g of CO2 and 4.66g of H2O. What is the empirical formula of the unknown compound?

CHO

Answer 1

Are you asking if CHO is correct. No it isn't.
Convert 11.4 g CO2 to grams C.
Convert 4.55 g H2O to grams H2.
Add the two and subtract from 5.70 g to find grams oxygen.

Then convert g C to moles. moles = grams/molar mass
Convert g hydrogen to moles (H atoms) = /
Convert g oxygen to moles O.

Then find the ratio of each with the smallest being 1.00. The easy way to do that is to divide the smallest value by itself (thereby assuring 1.00 for that element), then divide the other numbers by the same small value. Round to whole numbers.
Post your work if you get stuck.

Answer 2

C2H4O2