Electrolysis of water occurs according to the following equation... 2H20 ->2H2+O2

If electrolysis is performed with 100% efficiency on 100 grams of water. How many grams of hydrogen gas will be produced?

a. 11 grams
b. 50 grams
c. 4 grams
d. 100 grams

11.1g

Explanation:

Given parameters:

Mass of water  = 100g

Unknown:

Mass of hydrogen gas  = ?

Solution:

We need to write the balanced reaction equation first and solve from the known to the unknown;

       2H₂O  →  2H₂   +  O₂

Now, find the number of moles of the given specie;

 Number of moles of H₂O  =

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

Number of moles  =  = 5.56mol

   2 mole of water produced 2 mole of hydrogen gas;

  5.56 mole of water will produce 5.56 mole of hydrogen gas

     Mass of hydrogen gas = number of moles x molar mass

    molar mass  = 2(1)  = 2g/mol

    Mass of hydrogen gas  = 2(5.56) = 11.1g

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.

the answer your looking for is c).