The molecular mass of pyrene is 204.4 g/mol.
From;
ΔT = Kb m i
Where;
- ΔT = boiling point elevation
- Kb = boiling point constant
- m = molality
- i = Van't Hoff factor
Since the compound is molecular; i = 1
The number of moles of pyrene = 4.04 g/MM
Where; MM = molar mass of pyrene
molality = number of moles of pyrene/mass of solvent in Kg
The mass of solvent = 10 g or 0.01 Kg
molality = 4.04 g/MM/0.01
ΔT = Boiling point of solution - Boiling point of pure solvent
ΔT = 85.1°C - 80.1°C
ΔT = 5°C
5 = 2.53 × 4.04 g/MM/0.01 × 1
5 = 10.22 × 1/0.01 MM
0.05MM = 10.22
MM= 10.22/0.05
MM= 204.4 g/mol
Learn more: brainly.com/question/2292439
Answer:
the Answer is the second one
Explanation:
mole=mass/molar mass
mole=?
molar mass=142.1g/mole
mass=10.0g
Answer:
D. I < III < II
Explanation:
- The osmotic pressure (π) is given by the relation:
<em>π = iMRT.</em>
where, π is the osmotic pressure.
i is van 't Hoff factor.
M is the molarity of the solution.
R is the general gas constant.
T is the temperature.
<em>M, R and T are constant for all solutions.</em>
So, the osmotic pressure depends on the van 't Hoff factor.
- The van 't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass.
- For most non-electrolytes dissolved in water, the van 't Hoff factor is essentially 1.
- For most ionic compounds dissolved in water, the van 't Hoff factor is equal to the number of discrete ions in a formula unit of the substance.
For C₂H₆O₂ (non-electrolyte solute): i = 1.
For MgCl₂: i = 3.
It dissociates to give (Mg²⁺ + 2Cl⁻).
For NaCl: i = 2.
It dissociates to give (Na⁺ + Cl⁻).
So, the solute that has the highest osmotic pressure is II. 0.15 M MgCl₂, then III. 0.15 M NaCl, then I. 0.15 M C₂H₆O₂.
<em>D. I < III < II.</em>
<em></em>
Answer:
Should be A, but also I think there should be an arrow between O2 and 2H2O
Mrs Meador, because the water cycle is continuous and therefore has no clear end or beginning
