Answer:
Explanation:En la tabla periódica los elementos están ordenados de forma que aquellos con propiedades químicas semejantes, se encuentren situados cerca uno de otro. Los elementos se distribuyen en filas horizontales, llamadas períodos.
Answer:
[HF]₀ = 0.125M
Explanation:
NaOH + HF => NaF + H₂O
Adding 20ml of 0.200M NaOH into 25ml of HF solution neutralizes 0.004 mole of HF leaving 0.004 mole NaF in 0.045L with 0.001M H⁺ at pH = 3. This is 0.089M NaF and 0.001M HF remaining.
=> 45ml of solution with pH = 3 and contains 0.089M NaF from titration becomes a common ion problem.
HF ⇄ H⁺ + F⁻
C(eq) [HF] 10⁻³M 0.089M (<= soln after adding 20ml 0.200M NaOH)
Ka = [H⁺][F⁻]/[HF]₀ => [HF]₀ = [H⁺][F⁻]/Ka
[HF]₀ = (0.001)(0.089)/(7.1 x 10⁻⁴) M = 0.125M
Atoms are indivisible spheres-Dalton model
John Dalton was the first to propose a theory to describe matter. As per Dalton's model, all matter is composed of atoms which resemble tiny 'ball-like' structures that are indivisible.
Neon I think. Go to the periodic table and see which one is the 11th
