Question

A 1.50 g sample of a compound containing only C, H and O was burned in an attempt to determine its simplest formula. 3.00 g of CO2 and 1.23 g of H2O were collected. Find the simplest formula for the compound.

Answer 1

C2H4O (ut quest)

Answer 2

Step-by-step explanation:

The mass of carbon and hydrogen is calculated from the mass of their oxides (
`CO_(2)` and
`H_(2)O`) as follows.

Mass of C =
`3.00 g CO_(2) * (12.01 g C)/(44.0 g CO_(2))`

= 0.818 g C

Mass of H =
`1.23 g CO_(2) * (2.016 g H)/(18.02 g H_(2)O)`

= 0.137 g H

So, the mass of C + mass of H is as follows.

0.818 g + 0.137 g = 0.955 g

This mass is actually less than the mass of sample. And, the missing mass must be caused by O. Hence, the mass of O will be calculated as follows.

Mass of O = 1.50 g - 0.955 g

= 0.545 g

Now, we convert masses to moles and find their moles and ratio as follows.

Element Mass/g Moles Ratio
`* 2` Integers

C 0.818 0.068 1 2 2

H 0.137 0.068 1 2 2

O 0.545 0.0340 0.5 1 1

Thus, we can conclude that simplest formula for the given compound is
`C_(2)H_(2)O`.