The molar mass of Na₂SO₄ -
2 x Na - 2 x23 = 46
1 x S - 1 x 32 = 32
4 x O - 4 x 16 = 64
total = 46 + 32 + 64 = 142 g/mol
the molarity of solution - 2.0 M
in 1 L of solution , 2.0 moles
Therefore in 2.5 L - 2 mol/L x 2.5 L = 5 mol
then the mass of Na₂SO₄ required = 142 g/mol x 5 mol = 710 g
The reactions based on the absorption and release of the energy are called endothermic and exothermic reactions. The reaction is exothermic.
<h3>What is an exothermic reaction?</h3>
Exothermic reactions are the reaction in which the reactant produces products that release energy from the system to the surroundings. In the reaction bond energy of the reactant is less than the product.
Energy from the system is released in the form of heat, sound, light and electricity. The weak bonds of the compounds are replaced with stronger ones and the standard enthalpy of the reaction is negative.
Therefore, option c. reaction is exothermic is correct.
Learn more about the exothermic reactions here:
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The atom or an ion which loses electron /electrons is called reducing agent.
Whole moving across a period from left to right metallic character decreases, therefore reducing power element decreases.