Answer:
pH 8.89
Explanation:
English Translation
If the MgCl₂ solution of 0.2 M has its pH raised by adding NH₄OH, the precipitate will begin to form at a pH of approximately.
Given the solubility product (Ksp) of Mg(OH)₂ = 1.2 x 10⁻¹¹
Assuming all of the salts involved all ionize completely
MgCl₂ ionizes to give Mg²⁺ and Cl⁻
MgCl₂ ⇌ Mg²⁺ + 2Cl⁻
1 mole of MgCl₂ gives 1 moles of Mg²⁺
Since the concentration of Mg²⁺ is the same as that of MgCl₂ = 0.2 M
Mg(OH)₂ is formed from 1 stoichiometric mole of Mg²⁺ and 2 stoichiometric moles of OH⁻
Ksp Mg(OH)₂ = [Mg²⁺][OH⁻]²
(1.2 x 10⁻¹¹) = 0.2 × [OH⁻]²
[OH⁻]² = (6×10⁻¹¹)
[OH⁻] = √(6×10⁻¹¹)
[OH⁻] = 0.000007746 M
p(OH) = - log [OH⁻] = - log (0.000007746)
pOH = 5.11
pH + pOH = 14
pH = 14 - pOH = 14 - 5.11 = 8.89
Hope this Helps!!!
Answer:
It is pseudoscience because there are at least 118 known elements in nature.
Explanation:
Alchemy is an ancient branch of natural philosophy (not used much anymore).
I also just took the test and it's correct.
Answer:
0.5 centimetres
Explanation:
because 1 mm is 0.1 centimetres
Tap water used for drinking is considered in the DIL calculations; true
Im a bit torn here, lets look at the definitions of physical and chemical changes:
physical change changes only the phase/state of a substance, but not what the substance is
chemical change is a chemical reaction where a new substance is formed and energy is given off or absorbed.
(it just started raining and it smells really nice out my window)
clearly, this cannot be just a physical reaction. i think i would be inclined to pick B. but C. could have merit as an answer too. sorry for the ambiguity x
