Answer:
Kw = 2.88 × 10⁻¹⁵
Explanation:
Let's consider the dissociation of water.
H₂O(l) ⇄ H⁺(aq) + OH⁻(aq)
The equilibrium constant Kw is:
Kw = [H⁺].[OH⁻]
If pH = 7.27, we can find [H⁺]:
pH = -log [H⁺]
H⁺ = anti log (-pH) = anti log (-7.27) = 5.37 × 10⁻⁸ M
According to the balanced equation, 1 mole of H⁺ is produced per mole of OH⁻. So, [H⁺] = [OH⁻] = 5.37 × 10⁻⁸ M
Then,
Kw = [H⁺].[OH⁻]= (5.37 × 10⁻⁸)² = 2.88 × 10⁻¹⁵
O2- indicates an ion of oxygen having two extra electrons. I.e., since an oxygen atom normally has 8 protons and 8 electrons, this ion has 10 electrons (-10 charge) and 8 protons (+8 charge) giving it a charge of -2 (-10 + 8 = -2).
Answer:
Scandium
Explanation:
Mendeleev played an important role in the development of the modern periodic table. His periodic table was filled with gaps. He said that these gaps were elements that were yet to be discovered. He rightly predicted many elements which have now been discovered and fitted in their proper places in the periodic table.
He used the prefix ''eka'' to refer to elements whose properties were alike but were yet to be discovered at that time.
The compound named ekaboron which he predicted to have an atomic weight between 65 (zinc) and 75 (arsenic) with a valence similar to aluminum was later discovered in 1879 and properly named scandium.
Anytime an atom shares or transfers electrons a bond is formed, sharing= covalent and transfer= ionic
The answer is C. Only metallic alloys are malleable and ductile. The other descriptions can apply to all 3 answers
