Answer:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
Basis: 1 L of the substance.
(1.202 g/mL) x (1000 mL) = 1202 g
mass solute = (1202 g) x 0.2 = 240.2 g
mass solvent = 1202 g x 0.8 = 961.6 g
moles KI = (240.2 g) x (1 mole / 166 g) = 1.45 moles
moles water = (961.6 g) x (1 mole / 18 g) = 53.42 moles
1. Molality = moles solute / kg solvent
= 1.45 moles / 0.9616 kg = 1.5 m
2. Molarity = moles solute / L solution
= 1.45 moles / 1 L solution = 1.45 M
3. molar mass = mole solute / total moles
= 1.45 moles / (1.45 moles + 53.42 moles) = 0.0264
We determine the Coulombic force using the Coulomb's Law:
F = kQ₁Q₂/d²
where
k is equal to 9×10⁹ N·m²/C²
Q₁ and Q₂ are the charges of the two particles
d is the distance between them
For this problem, Q₁ = +2(0.16×10⁻¹⁸ C) and Q₂ = -2(0.16×10⁻¹⁸ C), because a single electron or proton has a charge of 0.16×10⁻¹⁸ C. The distance between the two ions is the sum of their radii.
d = radius of Ca²⁺ + radius of O²⁻
d = 0.106×10⁻⁹ m + 0.132×10⁻⁹ m
d = 0.238×10⁻⁹ m
F = (9×10⁹ N·m²/C²)(+2(0.16×10⁻¹⁸ C))(-2(0.16×10⁻¹⁸ C))/(0.238×10⁻⁹ m)²
F = 1.017×10¹¹ N
