Answer is: 28 kJ.
Chemical reaction: A₂ + B₂ ⇄ 2AB.
Ea(forward) = 105 kJ/mol.
Ea(reverse) = 77 kJ/mol.
ΔH(reaction) = ?
<span>The enthalpy change of reaction is the change in the energy of the reactants to the products.
</span>ΔH(reaction) = Ea(forward) - Ea(reverse).
ΔH(reaction) = 105 kJ/mol - 77 kJ/mol.
ΔH(reaction) = 28 kJ/mol; this is endothermic reaction (ΔH <span>> 0).</span>
Na⁺,SO₄²⁻ is the answer
<h3>Further explanation
</h3>
An ion is an atom or molecule that has a net electrical charge. There are many ions, one of them are sodium ion and sulfate ion.
SO₄²⁻ or Sulfate is a naturally occurring polyatomic ion that consist of a central sulfur atom surrounded by four oxygen atoms with occured widely in everyday life. Sodium ions are important for regulation of blood and body fluids, transmission of nerve impulses, heart activity, and certain metabolic functions.
Whereas Na⁺ or Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sulfate ion is a very weak base. Therefore sulfate ion undergoes negligible hydrolysis in aqueous solution.
Enter the symbol of a sodium ion, Na⁺, followed by the formula of a sulfate ion, SO₄²⁻. Separate the ions with a comma only—spaces are not allowed. Express your answers as ions separated by a comma. Therefore the answer is: Na⁺,SO₄²⁻
Hope it helps!
<h3>Learn more</h3>
- Learn more about sodium ion brainly.com/question/6839866
- Learn more about sulfate ion brainly.com/question/2763823
- Learn more about ions brainly.com/question/11852357
<h3>Answer details</h3>
Grade: 9
Subject: Chemistry
Chapter: Introduction to Mastering Chemistry
Keywords: sodium ion, sulfate ion, ions, Chemistry, symbol
Answer is: elements are always combined in the same proportion by mass.
Law of multiple proportions or Dalton's Law said that the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers.
For example, nitrogen(I) oxide N₂O; m(N) : m(O) = 2·14 : 16 = 7 : 4.
Another example, water (H₂O) is made of two hydrogen atoms and one oxygen atom:
m(H) : m(O) = 2·1 : 16 = 1: 8.
<span>Fill in the blanks: when an atom absorbs energy, the electrons move from their (ground) state to an (excited) state. when an atom emits energy, the electrons move from a(n) (excited) state to their (ground) state and give off (energy)</span>
