Bburette[1]
A burette measures to the nearest 0.05 cm3. A pipette measures one fixed volume and a measuring cylinder is less accurate.
Cuse a separating funnel, then find the boiling point[1]
Duse a separating funnel[1]
Immiscible liquids form layers, so they are separated with a separating funnel. Their boiling points are similar, so distillation does not work well.
Bsublimation[1]
Iodine changes straight from solid to gas on warming, leaving the sodium chloride behind.
BY by fractional distillation and Z using a separating funnel[1]
The liquid with the lower boiling point, Y, is collected first by fractional distillation. In a separating funnel the denser liquid, Z, is at the bottom and runs off first.
Aburette[1]
B0.61[1]
Rf = distance moved by Fdistance moved by the solvent front = 5590 = 0.61
Duse of a separating funnel[1]
Oil and water are immiscible and form two layers, so a separating funnel separates them.
Ciodine and sodium chloride[1]
The set-up is sublimation. Iodine sublimes and forms crystals on the cold funnel, while sodium chloride stays behind.
The blue dye and the yellow dye both have an Rf value of 0 (or almost 0) in pure water. [1]
There is no (or little) separation of the blue and yellow dyes. [1]
64% ethanol and 36% water [1]
All three dyes have the same Rf value (about 0.4) where the lines cross, so they form one spot.
Rf of the blue dye at 80% ethanol = 0.7 [1]
Distance travelled = 0.7 × 10.0 = 7.0 cm [1]
A locating agent is added to react with the amino acids and form coloured spots. [1]
Ultraviolet light can also be used for substances that show up under it.
S is the most soluble, as its Rf value is the highest in both solvents. [1]
Rf is the distance moved by the spot divided by the distance moved by the solvent, so the highest Rf means it travelled the furthest from the start line. [1]
Solvent 2, as all the amino acids are soluble in solvent 2. [1]
The Rf value of Q in solvent 1 is 0.00, which means it is insoluble in that solvent. [1]
Ethanol [1]
To make sure the condenser is fully filled with water, for more efficient cooling of the vapour into liquid. [1]
To measure the temperature of the vapour entering the condenser, which is the boiling point of the liquid being collected. [1]
No. Water and oil are immiscible. [1]
Propanol is a flammable liquid. or It gives more even heating around the flask. [1]
In Figure 1.2, the vapours escape into the surroundings, so less reactant is available for reaction. [1]
In Figure 1.1, the Liebig condenser condenses the vapours back into the flask, so more reactant is able to react to form more product. [1]
To react with the colourless spots and make them visible (coloured). [1]
Sample 2, as it has moved higher up the paper than sample 1. [1]
Rf = distance travelled by the sampledistance travelled by the solvent front [1]
Sample 1: Rf = 0.20 to 0.24 (with working). It is tartaric acid. [1]
Sample 2: Rf = 0.44 to 0.48 (with working). It is malic acid. [1]