The density of ethanol, C 2H 5OH, is 0.789 g/mL. How many milliliters of ethanol are needed to produce 25.0 g of CO 2 according to the following chemical equation? C 2H 5OH( l) + 3 O 2( g) → 2 CO 2( g) + 3 H 2O( l)

11.1mL

Explanation:

The reaction expression is given as:

          C₂H₅OH   + 3O₂ → 2CO₂ +  3H₂O

Given parameters:

density of ethanol  = 0.789g/mL

mass of CO₂ = 25g

Unknown:

Volume of ethanol = ?

Solution:

First find the number of moles of the CO₂ from the given mass;

 Number of moles  =

 Molar mass of CO₂ = 12 + 2(16) = 44g/mol

Number of moles  =    = 0.57mol

Then;

 Find the number of moles of ethanol used;

     3 moles of CO₂ is produced from 1 mole of ethanol;

    0.57mole of CO₂ will be produced from  = 0.19mole of ethanol

Now;

Find the mass of the ethanol from the given mole;

     Mass of ethanol  = number of moles x molar mass

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

      Mass of ethanol  = 0.19 x 46 = 8.74g

Then;

  Density is the mass per unit volume of a substance;

       Density  =

        Volume  =  

          Volume  =   = 11.1mL

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e