Answer:
Scientists believe that convection circulation within the mantle helps continents to move. As heat from Earth's innermost layer—the core—transfers to the bottom layer of mantle rock, the rock warms, softens, and rises upward. ... This churning motion in the mantle appears to be a major factor in plate movement.
Explanation:
The pH of the solution at 25 degree celsius of 1.3 × 10⁻⁶ moles of a sample of Sr(OH)₂ is 10.02.
<h3>How do we calculate pH?</h3>
The pH of any solution gives an idea about the acidic and basic nature of the solution and the equation of pH will be represented as:
pH + pOH = 14
Given that,
Moles of Sr(OH)₂ = 1.3 × 10⁻⁶ mol
Volume of solution = 25mL = 0.025L
The concentration of Sr(OH)₂ in terms of molarity = 1.3×10⁻⁶/0.025
= 5.2×10¯⁵M
Dissociation of Sr(OH)₂ takes place as:
Sr(OH)₂ → Sr²⁺ + 2OH⁻
From the stoichiometry of the reaction 1 mole of Sr(OH)₂ produces 2 moles of OH⁻.
Given that the base is a strong base and that it entirely dissociates into its ions, the hydroxide ion concentration is 5.2×10¯⁵×2 = 1.04×10¯⁴ M.
pOH = -log[OH⁻]
pOH = -log(1.04×10¯⁴)
pOH = 3.98
Now we put this value on the first equation we get,
pH = 14 - 3.98 = 10.02
Therefore, the value of pOH is 10.02.
Learn more about pH here:
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The amount of physical material in an object
There are 7 valence electrons in the atom :)
Polar Covalent.
This is because both Calcium (Ca) and Carbon (C) are non metals, thus eliminating the ionic option.
It is polar covalent rather than nonpolar covalent due to the fact that the electrons in a polar covalent bond are shared unequally while those in a nonpolar bond are shared equally.
This can be determined by looking at the amount of valence electrons; if the electrons cancel each other out, it is shared equally. If not, it is shared unequally.
Hope this helps!
