Question

2.911 grams of ethanol C2H5OH is burned and produces how many grams of water vapor?

Please help me or I'm dead.

Answer 1

3.4g

Step-by-step explanation:

Given parameters:

Mass of ethanol = 2.911g

Unknown:

Mass of water vapor = ?

Solution:

To solve this problem, let us write the balanced reaction equation first;

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

Now find the number of moles of ethanol;

Number of moles =
`(mass)/(molar mass)`

Molar mass of ethanol = 2(12) + 5(1) + 16 + 1 = 46g/mol

Number of moles =
`(2.911)/(46)` = 0.06mole

So;

1 mole of ethanol will produce 3 moles of water vapor

0.06mole of ethanol will produce 0.06 x 3 = 0.19moles of water vapor

Mass of water vapor = number of moles x molar mass

Molar mass of H₂O = 2(1) + 16 = 18g/mol

Mass of water vapor = 0.19 x 18 = 3.4g