8.1moles
Explanation:
Given parameters:
Mass of water to be decomposed = 29.2g
Unknown:
Number of moles of oxygen.
Solution:
To solve this problem, we first write the balanced reaction equation :
2H₂O → 2H₂ + O₂
Now convert the given mass of the water to number of moles;
Number of moles of water = 
Molar mass of water = 2(1) + 16 = 18g/mol
Number of moles of water = 
= 16.2moles
From the balanced reaction equation:
2 moles of water produced 1 mole of oxygen gas;
16.2 mole of water will produce 
= 8.1moles of oxygen gas
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The answer is 2.138 g of H2
A;4, b;6, c;7, d;5, e;8, f;3
Exothermic reaction is where there is release of energy during a reaction
The enthalpy of exothermic reaction is negative
The relation between energy of products, reactants and enthalpy of reaction is
Enthalpy of reaction = sum of enthalpy of formation of products - sum of enthalpy of formation of reactants
.
As enthalpy of reaction is negative, it means the enthalpy of products is less than the enthalpy of reactants so answer is
:
In an exothermic reaction the energy of the product is less than the energy of the reactants.
Total number of atoms = 7
Total number of H atom = 5
% of H in ammonium hydroxide = 5/7 ×100 = 71.4 %
