- Atoms that loss or gain electrons are called ions. There are two types of ions: cations and anions.
- Here, 2+ represents that Calcium (Ca) should gain 2 more electrons so that its number equals to that of protons.
- 3- represents that Nitrogen (N) should loss 3 electrons to equivalent with the number of protons.
- Here, anions are S^2-, P^3-, Se^2-, Br^-.
- While cations are Cr^3+, Ag^+, Li^+, Ba^2+.
- The number of protons of Magnesium (Mg) = 12
- The number of nuetrons of Mg = 12
- The number of electrons of Mg = 12
Hope you could get an idea from here.
Doubt clarification - use comment section.
Li because its charge is +1.
Answer is: ph value is 3.56.
Chemical reaction 1: H₂CO₃(aq) ⇄ HCO₃⁻(aq) + H⁺(aq); Ka₁ = 4,3·10⁻⁷.
Chemical reaction 2: HCO₃⁻(aq) ⇄ CO₃²⁻(aq) + H⁺(aq); Ka₂ = 5,6·10⁻¹¹.
c(H₂CO₃) = 0,18 M.
[HCO₃⁻] = [H⁺<span>] = x.
</span>[H₂CO₃] = 0,18 M - x.
Ka₁ = [HCO₃⁻] · [H⁺] / [H₂CO₃].
4,3·10⁻⁷ = x² / (0,18 M -x).
Solve quadratic equation: x = [H⁺] =0,000293 M.
pH = -log[H⁺] = -log(0,000293 M).
pH = 3,56; second Ka do not contributes pH value a lot.
Calculate the mass of the solute <span>in the solution :
Molar mass KCl = </span><span>74.55 g/mol
m = Molarity * molar mass * volume
m = 0.9 * 74.55 * 3.5
m = 234.8325 g
</span><span>To prepare 0.9 M KCl solution, weigh 234.8325 g of salt in an analytical balance, dissolve in a beaker, shortly after transfer with the help of a funnel of transfer to a volumetric flask of 100 cm</span>³<span> and complete with water up to the mark, then cover the balloon and finally shake the solution to mix
hope this helps!</span>
Higher. Because this type of heat transfer is conduction, meaning that heat always transfers to cooler objects.
