Câu 2: (0,5 đ) Tính số ml H3PO4 85% (d=1,69 g/ml) phải lấy để hòa tan vào nước và pha loãng thành 500 ml thì pH = 3.
Biết axit H3PO4 có có pKal=2,15; pKaz=7,31; pKa3= 12,32.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.