Cotton is opaque. Opaque objects do not let light pass through. You can't see through the objects that are opaque.
We calculate the molar concentration [Cl⁻] using stoichiometry. MnCl2(aq) is an ionic compound which will have the releasing of 2 Cl⁻ ions ions in water for every molecule of MnCl2 that dissolves.
MnCl2(s) --> Mn+(aq) + 2 Cl⁻(aq)
[Cl⁻] = 0.68 mol MnCl2/1L × 2 mol Cl⁻ / 1 mol MnCl2 = 1.4 M
The answer to this question is [Cl⁻] = 1.4 M
The atom's center, or nucleus, is positively charged and the electrons that whirl around this nucleus are negatively charged, so they attract each other. The reason the force is strong is because the atom is so small. The distance between the nucleus and the electrons is about 1 Angstrom (named after a famous scientist); this is 0.00000001 cm (10-8 cm) or about 4 billionths of an
