We can predict the order of the elements given above according from the highest to lowest first ionization energies by using the trends in a periodic table. For elements in a family, the ionization energy decreases as it goes down. Therefore, the correct order would be Be, Mg, Ca, Sr.
1) Find the number of molecules in 7.88 g of sulfur
molar mass of S8 = 8*atomic mass of S = 8 * 32.0 g / mol = 256.0 g/mol
Number of moles = mass in grams / atomic mass = 7.88 g / 256.0 g / mol = 0.0308 moles
2) Find the mass of 0.0308 moles of P4
mass = number of moles * molar mass
molar mass of P4 = 4 * atomic mass of P = 4 * 31 g/mol = 124 g/mol
mass of P4 = 0.0308 moles * 124 g/mol = 3.8192g ≈ 3.82 g.
Answer: 3.82 grams of P4 will have the same number of molecules as 7.88 g of S8 (that is 0.0308 moles of molecules)
3 Mg + 1 Fe2O3 →2 Fe + 3MgO
Type of Reaction: Single displacement.
Acid more H3O+ than OH-
Base less H3O+ than OH-
Chlorous Acid Ionizes as,
HClO₂ ⇆ H⁺ + ClO₂⁻
Ka = [H⁺] [ClO₂⁻] / [HClO₂]
Ka of Chlorous Acid = 1.1 × 10⁻²
The concentration of H⁺ ions at equilibrium are calculated as,
Initial 0.1 M ⇆ 0 0
At Equilibrium 0.1-X ⇆ X X
So,
Ka = [X] [X] / [0.1-X]
Putting value of Ka,
1.1 × 10⁻² = X² / 0.1-X
Solving for X,
(www.cymath.com)
X = 0.028 M
Hence at equilibrium concentration of H⁺ and ClO₂⁻ is 0.028 M.
Percentage Ionization is calculated as,
= [H⁺] / [HA] × 100
= (0.028 / 0.1) × 100
= 0.28 × 100
= 28 % (Percentage Ionization)
