Answer:
The general equation for an exothermic reaction is: Reactants → Products + Energy.
Answer is: the hydronium ion concentratio is 1.71×10⁻⁷ mol/dm³ and pH<6.76.
The Kw (the ionization constant of water) at 40°C is 2.94×10⁻¹⁴ mol²/dm⁶ or 2.94×10⁻¹⁴ M².
Kw = [H₃O⁺] · [OH⁻].
[H₃O⁺] = [OH⁻] = x.
Kw = x².
x = √Kw.
x = √2.94×10⁻¹⁴ M².
x = [H₃O⁺] = 1.71×10⁻⁷ M; concentration of hydronium ion.
pH = -log[H₃O⁺].
pH = -log(1.71×10⁻⁷ M).
pH = 6.76.
pH (potential of hydrogen) is a numeric scale used to specify the acidity or basicity an aqueous solution.
Mass number is the number of protons and neutrons in an atom, and it tells us about the mass of the atom in amu, or atomic mass units. Atomic mass is the average mass of all the isotopes of a certain type. It is a weighted average that takes into account the abundances of all of the different isotopes
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A stoichiometric mixture is a mixture of fuel and oxygen for which the masses of these two components are exactly those needed for complete combustion.
A stoichiometric mixture is a balanced mixture of fuel and oxygen.
The fuel and the oxygen react completely without the excesses of either.
The opposite of a stoichiometric mixture is called feeding an excess, when minimum one reactant is an excess amount.
Balanced chemical equation for reaction of combustion one type of a fuel: C₈H₁₈ + 25/2O₂ → 8CO₂ + 9H₂O
Stoichiometric mixture for this example is when fuel (C₈H₁₈) and oxygen(O₂) react in proportion 1 : 12.5.
More about a stoichiometric mixture: brainly.com/question/19585982
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