Question

Consider the mixture of ethanol, c2h5oh, and o2. how many molecules of co2, h2o, c2h5oh, and o2 will be present if the reaction goes to completion?

Answer 1

Answer : The number of molecules of
`CO_2,H_2O,C_2H_5OH\text{ and }O_2` are 2, 3, 1 and 3 respectively.

Explanation :

The given balanced chemical reaction is,

`C_2H_5OH+3O_2\rightarrow 2CO_2+3H_2O`

Balanced chemical reaction is the reaction in which the number of atoms of an individual elements present on reactant side must be equal to the product side.

The species present on the left side of the right arrow is the reactant and the species present on the right side of the right arrow is the product.

From the balanced chemical reaction, we conclude that there are 1 molecule of
`C_2H_5OH`, 3 molecules of
`O_2`, 2 molecules of
`CO_2` and 3 molecules of
`H_2O`.

Answer 2

The reaction between ethanol and oxygen must be a combustion reaction to give carbon dioxide and water as products.

The reaction between ethanol,
`C_2H_5OH` and oxygen,
`O_2` is as follows:

`C_2H_5OH+O_2\rightarrow CO_2+H_2O`

In order to balance the reaction (the number of atoms of each element in the reaction are same on both the sides that is product and reactant),
`O_2` is multiplied by 3 in the reactant side and
`CO_2` is multiplied by 2 and
`H_2O` is multiplied by 3 on product side.

So, the balanced reaction is:

`C_2H_5OH+3O_2\rightarrow 2CO_2+3H_2O`

From the balanced reaction it is clear that 1 mole of
`C_2H_5OH` reacts with 3 moles of
`O_2` to give 2 moles of
`CO_2` and 3 moles of
`H_2O`.

Since, 1 mole =
`6.022* 10^(23)` molecules (Avogadro's number)

So,

Number of molecules of
`C_2H_5OH` =
`6.022* 10^(23)` molecules.

Number of molecules of
`O_2` =
`6.022* 10^(23)* 3 = 18.066* 10^(23)` molecules.

Number of molecules of
`CO_2` =
`6.022* 10^(23)* 2 = 12.044* 10^(23)` molecules.

Number of molecules of
`H_2O` =
`6.022* 10^(23)* 3 = 18.066* 10^(23)` molecules.