Question

the student measured the distance between points 6 and 5, the top edge of the solvent, as 13 cm and the distance between 6 and the yellow pigment is 8.8 cm. calculate the rf value for the yellow pigment and enter your response using two significant figures.

Explanation:

Step1: Recall Rf formula

The formula for the retention factor (\(R_f\)) is \(R_f=\frac{\text{Distance traveled by the solute}}{\text{Distance traveled by the solvent front}}\).

Step2: Identify distances

Distance traveled by solvent front (between 6 and 5) is \(13\space\text{cm}\). Distance traveled by yellow pigment (between 6 and yellow) is \(8.8\space\text{cm}\).

Step3: Calculate \(R_f\)

Substitute into the formula: \(R_f = \frac{8.8}{13}\). Calculate this division: \(\frac{8.8}{13}\approx0.68\) (rounded to two significant figures).

Answer:

\(0.68\)