Analytical Chemistry Trivia Quiz

Answer: Spectrophotometric analysis - density

Actually, spectrophotometric exploits the light properties of chemical compounds. In a spectophotometric analysis, one measures how much light is absorbed by a certain solution.

Classical methods include gravimetric analysis and volumetric analysis. On the other hand, instrumental methods include spectophotometric analysis and potentiometric analysis.

Answer: Part per million (ppm)

For example, a solution with a concentration of 1.5 ppm sodium is interpreted as there is only 1.5 milligram of sodium in 1 liter of solution.

The concentration of salt (sodium chloride) in typical sea water is around 32-35 ppt. 1 ppt (part per thousand) means 1 milligram per 1 liter of solution)

Answer: Q test

The F test is used to test whether the standard deviations for 2 sets of data are significantly different from each other. On the other hand, the T test, also known as the Student T test, is used to compare the obtained value in experiments with the real (actual) value.

Answer: The Le Chatelier's Principle

This principle is named after Henry Louis Le Chatelier. He was born in Paris, France in 1850.

Answer: Both of these

Notice that Na3PO4 is not an amphoteric salt, because it can only donate proton (H+), but cannot receive proton.
The sequence below shows how Na3PO4 can donate its proton stepwise, and finally forming H3PO4.
Na3PO4---> Na2HPO4 ---> NaH2PO4---> H3PO4

Answer: Nitrogen, N

The nitrogen in a substance will react with sulfuric acid, H2SO4 to produce ammonia, NH3. The ammonia produced will then be neutralized by sodium hydroxide, NaOH. The excess NaOH will be neutralized again with hydrochloric acid, HCl.

Using the backward calculation, we will know the percentage of nitrogen in the given substance.

Answer: Hexadentate ligand

A monodentate ligand only has one lone pair of electron that can be donated to the metal ion. Bidentate has two and tetradentate has four. For example, water (containing 2 lone pairs of electrons) is a bidentate ligand, while ammonia (containing a lone pair of electrons) is a monodentate ligand. An EDTA molecule has 6 lone pairs of electrons (4 from the H+ nand 2 from the diamine groups). Hence, it is a hexadentate liugand.

For complexometric analysis, the pH of the solution is normally buffered at pH 11 to give a maximum yield of the Y^4- species (from the H4Y EDTA) that we desire. Y^4- will combine with metal ion, M^2+ to form chelate, MY^2-.

Answer: Matrix

For example, we wish to calculate the percentage of arsenic in a food sample for a food poisoning case. So, the analyte here is arsenic, while the rest of the compounds in the food sample are matrices.

Answer: Haber's method

The Haber's process is used for the manufacturing of ammonia, NH3. The Mohr's method requires a blank analysis and it is usually carried out in a slightly basic solution.

On the contrary, the Volhard's method is carried out in an acidic medium, and it requires back titrations. Lastly, the Fajan's method uses indicators such as dichlorofluorescein. The colloidal particles that are formed will react with the indicator to produce a complex of different colour, indicating the end point has been reached for the chemical reaction.

Answer: Starch

For iodimetry, iodine is added to a solution and the end point is signaled by the change of colour from a colourless solution to a blue colour.

In contrast, a change from blue colour to a colourless solution signals the end point for the iodometry analysis, where excess iodide is added to the solution.