Answer:
Rf = 0.26
Explanation:
The Rf value is calculated by dividing the distance traveled by a compound, by the distance traveled by the solvent front. In other words, the length of the TLC plate is not relevant in calculating a Rf value.
- Distance traveled by compound C = 18 mm
- Distance traveled by the solvent front = 70 mm
Answer:
Explanation:
<u>1) Data:</u>
a) Solute: acetone
b) Solvent: benzene
c) n (solute) = 0.863 mol
d) mass of solvent = 500 g = 0.500 Kg
e) ΔTf = 8.84 °C
f) Kf = ?
<u>2) Formulae:</u>
- Depression of freezing point: ΔTf = m . Kf
- Molality: m = n (solute) / kg solvent
<u>3) Solution:</u>
a) m = 0.863 mol / 0.500 kg = 1.726 m
b) Kf = ΔTf / m = 8.84°C / 1.726 m = 5.12 °C/m ← answer
Definition of melting point:
The melting point of solid is defined as the temperature at which the solid exists in equilibrium with its liquid under an external pressure of one atmosphere.
Reason:
The melting point is an important physical property of a compound.
1) The melting point can be used to identify a substance.
2) As an indication of its purity.
