Answer:
a. Xm = 0.0229
b. 0.0234 moles
c. 354.1 g/mol
Explanation:
ΔP = P° . Xm
ΔP = P° - P', where P° is vapor pressure of pure solvent and P', vapor pressure of solution-
This is the formula for lowering vapor pressure.
If we apply the data given: 523 Torr - 511 Torr = 523 . Xm
Xm = ( 523 Torr - 511 Torr) / 523 Torr → 0.0229
Xm = Mole fraction of solute → Moles of solute / Total moles (sv + solute)
We can make this equation to determine moles of solute
0.0229 = Moles of solute / Moles of solute + 1
0.0229 (Moles of solute + 1) = Moles of solute
0.0229 = Moles of solute - 0.0229 moles of solute
0.0229 = 0.9771 moles of solute → 0.0229 / 0.9971 = 0.0234 moles
Molecular mass of solute → g/mol → 8.3 g / 0.0234 mol = 354.1 g/mol
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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Answer:
8m/min
Explanation:
120 m / 15 min = 8 meters per min
The Chemistry Regents is one of the four science Regents exams. The other three are Earth Science, Living Environment, and Physics. You'll need to pass at least one of these four exams to graduate high school.
Answer:10g of Fe produces 14.37g of Fe2O3
7g of O2 produce 46.84g of Fe2O3
Explanation:
