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A 1.000 gram sample of an alcohol was burned in oxygen to produce 1.913 g of CO2 and 1.174 g of H20. The alcohol contained only C, H, and O. What is the simplest formula of the alcohol?

2 Answers

5 votes
the formula of alcohol are
1.913 g CO2/44 = 0.043 moles of CO2*12 = 0.043 moles of C 1.174 gram H2O/18 = 0.065 moles of H.
O: 1 - 0.516 g C - 13 g H = 0.354 g O/16 = 0.022 moles of O.
we have 0.043:0.130.;0.022 as C:H:O. Diving by the smallest no. 0.022 we get 1.95:5.9:1 or 2:6:1 as C:H:O.

hope this help
User Trustin
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5 votes

Answer: The simplest formula of the alcohol is,
C_2H_6O

Step-by-step explanation:

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:


C_xH_yO_z+O_2\rightarrow CO_2+H_2O

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of
CO_2=1.913g

Mass of
H_2O=1.174g

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44 g of carbon dioxide, 12 g of carbon is contained.

So, in 1.913 g of carbon dioxide,
(12)/(44)* 1.913=0.522 of carbon will be contained.

For calculating the mass of hydrogen:

In 18 g of water, 2 g of hydrogen is contained.

So, in 1.174 g of water,
(2)/(18)* 1.174=0.130g of hydrogen will be contained.

Mass of oxygen in the compound = (1.000) - (0.522 + 0.130) = 0.348 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Carbon =
\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=(0.522g)/(12g/mole)=0.0435moles

Moles of Hydrogen =
\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=(0.130g)/(1g/mole)=0.130moles

Moles of Oxygen =
\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=(0.348g)/(16g/mole)=0.022moles

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.022 moles.

For Carbon =
(0.0435)/(0.022)=1.97\approx 2

For Hydrogen =
(0.130)/(0.022)=5.9\approx 6

For Oxygen =
(0.022)/(0.022)=1

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : O = 2 : 6 : 1

The empirical formula for the given compound is
C_2H_6O_1=C_2H_6O

Therefore, the simplest formula of the alcohol is,
C_2H_6O

User Jonathon Marolf
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