Question

A student preforms a chemical reaction in which 35 grams of hydrogen and 65 grams of oxygen reacted to form water. What is the mass of the products?

Answer 1

Answer:

Mass of water = 73.08 g

Explanation:

Given data:

Mass of hydrogen = 35 g

Mass of oxygen = 65 g

Mass of water = ?

Solution:

First of all we will write the balanced chemical equation:

2H₂  + O₂   →    2H₂O

Number of moles of hydrogen = mass/ molar mass

Number of moles of hydrogen =  35 g/ 2 g/mol

Number of moles of hydrogen = 17.5 mol

Number of moles of oxygen = 65 g / 32 g/mol

Number of moles of oxygen = 2.03 moles

Now we compare the moles of water with moles hydrogen and oxygen.

                                     H₂               :              H₂O

                                      2                :                2

                                    17.5              :              17.5

                                       O₂             :            H₂O

                                      1                :               2

                                      2.03         :             2× 2.03 =4.06 mol

Number of moles of water produced by oxygen are less so oxygen is limitting reactant.

Mass of water:

           Mass of water = number of moles × molar mass

          Mass of water = 4.06 mol × 18 g/mol

           Mass of water = 73.08 g