In Thin Layer Chromatography (TLC), how do you interpret the results in terms of the relative polarity of the pigments separated? The phase that moves the farthest is least polar. The stationary phase is less polar than the mobile phase. The mobile phase is more polar than the stationary phase. The phase that remains closest is least polar.

The phase that moves the farthest is least polar.

What is the formula to calculate the Rf value in TLC, and what is its significance? Rf = distance moved by solvent front / distance moved by substance; it indicates absolute polarity. Rf = distance moved by substance + distance moved by solvent front; it indicates molecular weight. Rf = distance moved by substance / distance moved by solvent front; it indicates relative polarity. Rf = distance moved by solvent front - distance moved by substance; it indicates solubility.

Rf = distance moved by substance / distance moved by solvent front; it indicates relative polarity.

When comparing the number and types of pigments in mixtures analyzed by TLC, what factors should be considered? Only the color and distance traveled. Rf value and solubility. Polarity and molecular weight. Distance traveled, color, polarity, and Rf value.

Distance traveled, color, polarity, and Rf value.

What is the procedure for conducting a TLC lab to separate ink components? Apply ink to the center of the paper, dip in water, and observe diffusion. Mix ink with solvent, heat, and observe color change. Apply ink near the end of the paper, dip in mobile phase, and observe separation. Apply ink to the top of the paper, dip in oil, and observe sedimentation.

Apply ink near the end of the paper, dip in mobile phase, and observe separation.

What are the purposes of using Thin Layer Chromatography (TLC) in a laboratory setting? To measure temperature changes, determine pH levels, and analyze viscosity. To calculate molecular weight, determine boiling points, and analyze solubility. To establish compound identity, determine mixture components, and monitor reactions. To observe color changes, measure density, and analyze thermal conductivity.

To establish compound identity, determine mixture components, and monitor reactions.

How do you choose the best wavelength for absorbance measurement in spectrophotometry? Choose the wavelength with the highest peak. Choose any wavelength as it does not affect the results. Select the wavelength with the lowest point. Select a wavelength with a flatter curve to minimize uncertainty.

Select a wavelength with a flatter curve to minimize uncertainty.

How do you dilute a stock solution to create a standard curve of absorbance as a function of concentration? Use the formula mv=mv, adjust molarity, and solve for volume. Heat the solution until it evaporates, then measure absorbance. Add solvent until the solution is clear, then measure absorbance. Mix equal parts of stock and solvent, then measure absorbance.

Use the formula mv=mv, adjust molarity, and solve for volume.

How can you use the absorbance-concentration relationship to find the concentration of an unknown solution? Plot absorbance vs. concentration for standards, then use the graph to find unknown concentration. Dilute the unknown solution until it matches the color of a standard. Measure the absorbance of the unknown and compare it to a color chart. Use a pH meter to determine the concentration based on acidity.

Plot absorbance vs. concentration for standards, then use the graph to find unknown concentration.

Using Beer's Law, how do you calculate the concentration of a substance in solution given the molar absorptivity constant? A = ac; solve for b using given A and c. A = bc; solve for a using given A and c. A = ab; solve for c using given A and b. A = abc; solve for c using given A and a.

A = abc; solve for c using given A and a.

What is the procedure for determining the reaction order of crystal violet using a Beer's Law calibration curve? Heat crystal violet with sodium hydroxide, measure temperature, and observe reaction. Mix crystal violet with water, measure pH, and observe color change. Dissolve crystal violet in alcohol, measure density, and analyze solubility. Select wavelength, prepare dilutions, measure absorbance, and analyze rate law.

Select wavelength, prepare dilutions, measure absorbance, and analyze rate law.

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