Answer:
0.1714 (w/w) %
Explanation:
Utilizando la ecuación:
16H+(aq) + 2Cr2O72−(aq) + C2H5OH(aq) → 4Cr3+(aq) + 2CO2(g) + 11H2O(l)
Se emplean 2 moles de ion dicromato (Cr₂O₇²⁻) para titular 1 mol de alcohol (C₂H₅OH)
35.46mL = 0.03546L de una solución de Cr₂O₇²⁻ a 0.05961M utilizada para alcanzar el punto de equivalencia en la titulación contiene:
0.03546L ₓ (0.05961 moles Cr₂O₇²⁻ / L) = 2.114x10⁻³ moles Cr₂O₇²⁻
Dado que 2 moles de dicromato reaccionan por cada mol de alcohol, los moles de alcohol en la muestra de plasma son:
2.114x10⁻³ moles Cr₂O₇²⁻ ₓ ( 1 mol C₂H₅OH / 2 moles Cr₂O₇²⁻) = 1.0569x10⁻³ moles de C₂H₅OH
Como la masa molar del alcohol es 46.07g/mol, la masa de alcohol es:
1.0569x10⁻³ moles de C₂H₅OH ₓ (46.07g / mol) = 0.04869g de C₂H₅OH
Por lo tanto, el porcentaje en masa de alcohol en sangre utilizando los 28.40g de plasma es:
(0.04869g de C₂H₅OH / 28.40g) × 100 = 0.1714 (w/w) %
Answer:
The solution's absorbance measures 0.21168.
Explanation:
Provided that,
Wavelength = 500 nm
Molar absorptivity = 252 M⁻¹ cm⁻¹
Moles present = 0.00140
Total solution volume = 500.0 mL
Path length = 3.00 mm
We have to determine the molar concentration
Utilizing the formula for molar concentration
Where N = number of moles
V = volume
Input the values into the formula
Next, we will calculate the solution's absorbance
Using the absorbance formula
Substituting values into the equation
Therefore, the absorbance of the solution is 0.21168.
The result is 1.4 x 10^-5m^3. Remember to consider the cubic measurement in your calculations.
To calculate the average atomic mass of an element, you can multiply the masses of its isotopes by their corresponding relative abundances and sum them up.
Average atomic mass of Br = 158 amu(0.2569) + 160 amu(0.4999) + 162 amu(0.2431)
Average atomic mass = 159.96 amu
According to the information given, the relative abundance of Br-79 stands at 25.69% because two atoms of Br yield 79*2 = 158 amu. Likewise, for Br-81, the relative abundance is 162 due to 81*2 = 162, which is 24.31%.
3.25 kg in grams = 3.25 * 1000 = 3250 g
Molar mass of C₂H₆O₂ = 62.0 g/mol
Mass of solvent = 7.75 kg
Number of moles:
n = mass of solute / molar mass
n = 3250 / 62.0
n = 52.419 moles
Molality = moles of solute / kilograms of solvent
M = 52.419 / 7.75
M = 6.7637 mol/kg
I hope this clarifies things!
