Answer:
Molar mass→ 0.930 g / 6.45×10⁻³ mol = 144.15 g/mol
Explanation:
Let's apply the formula for freezing point depression:
ΔT = Kf . m
ΔT = 74.2°C - 73.4°C → 0.8°C
Difference between the freezing T° of pure solvent and freezing T° of solution
Kf = Cryoscopic constant → 5.5°C/m
So, if we replace in the formula
ΔT = Kf . m → ΔT / Kf = m
0.8°C / 5.5 m/°C = m → 0.0516 mol/kg
These are the moles in 1 kg of solvent so let's find out the moles in our mass of solvent which is 0.125 kg
0.0516 mol/kg . 0.125 kg = 6.45×10⁻³ moles. Now we can determine the molar mass:
Molar mass (mol/kg) → 0.930 g / 6.45×10⁻³ mol = 144.15 g/mol
Answer:
pOH= 14.248
[H+]=1.77 M
[OH-]=5.65 x10^-15M
Explanation:
pH+pOH= 14
pOH= 14-pH
pOH=14-(-0.248)
pOH= 14.248
[H+]=10^-pH= 10^-(-0.248)=1.77 M
[OH-]=10^-pOH= 10^-14.248=5.65 x10^-15M
Answer:
The particles that make up a substance in its liquid state have <u>more </u>kinetic energy than those of the same substance in its solid-state.
For a solid to melt, energy must be <u>added to</u> the system.
For a liquid to freeze, energy must be <u>removed from</u> the system.
