Answer:
M1 = 49.04 g/mol
Explanation:
The pure benzonitrile has freezing point -12.8°C. By adding a nonvolatile compound, the freezing point will be changed, a process called cryoscopy. The freezing point will be reduced. In this case, the new freezing point is -13.4°C. The variation at the temperature can be calculated by the equation:
ΔT = Kc*W*i
Where ΔT is the variation at the freezing temperature (without the solute less with the solute), Kc is the cryoscopy constant (5.34 for benzonitrile), W is the molality, and i the Van't Hoff correction factor, which is 1 for benzonitrile.
((-12.8-(-13.4)) = 5.34*W
5.34W = 0.6
W = 0.1124 mol/kg
W = m1/M1*m2
Where m1 is the mass of the solute (in g), M1 is the molar mass of the solute (in g/mol), and m2 is the mass of the solvent (in kg).
m1 = 0.551 g, m2 = 0.1 kg
0.1124 = 0.551/M1*0.1
0.01124M1 = 0.551
M1 = 49.04 g/mol
I believe Fission i'm not 100% sure though
Answer:
56.9 mmoles of acetate are required in this buffer
Explanation:
To solve this, we can think in the Henderson Hasselbach equation:
pH = pKa + log ([CH₃COO⁻] / [CH₃COOH])
To make the buffer we know:
CH₃COOH + H₂O ⇄ CH₃COO⁻ + H₃O⁺ Ka
We know that Ka from acetic acid is: 1.8×10⁻⁵
pKa = - log Ka
pKa = 4.74
We replace data:
5.5 = 4.74 + log ([acetate] / 10 mmol)
5.5 - 4.74 = log ([acetate] / 10 mmol)
0.755 = log ([acetate] / 10 mmol)
10⁰'⁷⁵⁵ = ([acetate] / 10 mmol)
5.69 = ([acetate] / 10 mmol)
5.69 . 10 = [acetate] → 56.9 mmoles
Answer:
15.37 atm
Explanation:
According to Dalton's law of partial pressure, the total pressure of a mixture of gases in the tank is a sum of the individual pressures of all the gases. Hence;
PT = P1 + P2 + P3 -----------
So;
Ptotal = Phelium + Poxygen
Poxygen = 4.63 atm
Ptotal = 20.0 atm
Phelium = 20.0 atm - 4.63 atm
Phelium = 15.37 atm
