Answer:
2.7 °C.kg/mol
Explanation:
Step 1: Calculate the freezing point depression (ΔT)
The normal freezing point of a certain liquid X is-7.30°C and the solution freezes at -9.9°C instead. The freezing point depression is:
ΔT = -7.30 °C - (-9.9 °C) = 2.6 °C
Step 2: Calculate the molality of the solution (b)
We will use the following expression.
b = mass of solute / molar mass of solute × kilograms of solvent
b = 102. g / (162.2 g/mol) × 0.650 kg = 0.967 mol/kg
Step 3: Calculate the molal freezing point depression constant Kf of X
Freezing point depression is a colligative property. It can be calculated using the following expression.
ΔT = Kf × b
Kf = ΔT / b
Kf = 2.6 °C / (0.967 mol/kg) = 2.7 °C.kg/mol
Answer:
The answer is 18.12KJ is required to vaporise 48.7 g of dichloromethane at its boiling point
Explanation:
To solve the above question we have the given variable as follows
ΔHvap = heat of vaporisation of dichloromethane per mole = 31.6KJ/mole
However since the heat of vaporisation is the heat to vaporise one mole of dichloromethane, then, for 48.7 grams of dichloromethane, we have.
The number of moles of dichloromethane present = 48.7/84.93 = 0.573 moles
Therefore, the amount of heat required to vaporise 48.7 grams of dichloromethane at its boiling point is 31.6KJ/mole×0.573moles =18.12KJ
The primary form of heat transfer taking place within the water bottle will be convection, which is the natural circulation of fluid due to density differences arising from temperature differences.
The second form is dependent on how the heating is taking place. If the bottle is out in sunlight, the form of heat transfer is radiation from the sun's rays. If heat is directly being applied to it, then the form is conduction, which occurs in solids and through direct contact.
<span>No. Zn can only have oxidation states of 1+ or 2+. For this compound to be able to exist, the Zn would have to have an oxidation state of 2- to counteract the 2+ from the 2 sodium ions. Sodium ions each have a +1 charge, so the 2 sodium ions would carry a +2 charge. In order for the compound to exist, the net charge between the 2 sodium and 1 zinc atoms would need to be 0.</span>
<span>((P1V1/T1)=(P2V2/T2))</span>
