Question

q1 chemistry! utl6 mixture separation plan date: ____ prepwork prepwork part 1: directions: read the scenario below and answer the questions that follow. oswald, the octopus that sits on ms. davies’s desk, has gone missing! in his place, someone has left a note, containing a list of demands for his safe return. ms. davies can only think of two options: caving to the thief’s demands or figuring out who did it before the deadline. the note was written in black marker. fortunately, all of the black markers in ms. davies’s room are labeled to identify who they belong to. unfortunately, there are several black markers scattered on the table near where the note was found and it is not obvious which one was used to write the note. because ms. davies has studied chemistry, she knows that each type of black marker has a slightly different combination of pigments in the ink. based on this, she thinks she can come up with a plan to determine which marker was used to write the note. 1. what separations technique could be used to determine the pigments used in each marker? justify your response. ___________ 2. what property of the pigments is this technique based on? _____________

Explanation:

Question 1

To determine the pigments in marker ink, chromatography (specifically paper chromatography or thin - layer chromatography) can be used. Marker ink is a mixture of different pigments. In chromatography, a sample (ink from the marker) is placed on a stationary phase (like paper or a thin - layer plate). A mobile phase (solvent) moves through the stationary phase. Different pigments in the ink will have different affinities for the stationary and mobile phases. Pigments that are more soluble in the mobile phase and have less attraction to the stationary phase will move faster and travel a greater distance, while those with more attraction to the stationary phase and less solubility in the mobile phase will move slower. By comparing the chromatograms (the patterns of separated pigments) of the ink from the note and the inks from the various markers, we can identify which marker was used.

The chromatography technique for separating marker ink pigments is based on the different solubility of the pigments in the mobile phase (solvent) and their different adsorption (attraction) to the stationary phase (e.g., paper or thin - layer plate). Pigments that are more soluble in the mobile phase and less adsorbed to the stationary phase will travel further up the stationary phase, while those with lower solubility in the mobile phase and higher adsorption to the stationary phase will travel a shorter distance.

Answer:

A separation technique that could be used is chromatography (e.g., paper chromatography or thin - layer chromatography). Justification: Marker ink is a mixture of pigments. Chromatography separates components of a mixture based on their differential partitioning between a mobile phase (solvent) and a stationary phase (e.g., paper or a thin - layer plate). Different pigments in the ink will have different solubilities in the mobile phase and different attractions to the stationary phase, causing them to move at different rates and separate. By comparing the chromatographic patterns of the ink from the note with those of the inks from the available markers, we can determine which marker was used.

Question 2