Wacker Metroark Chemicals QC Chemist Interview Questions and Answers

Samples can be identified based on labeling, appearance, unique characteristics, and accompanying documentation.

• Check the labeling on the sample containers for identification information such as sample name, ID number, and date collected.

• Examine the physical appearance of the samples, noting color, texture, and any visible impurities.

• Look for unique characteristics such as odor or solubility that can help differentiate...read more

NMR spectroscopy is a technique used to study the structure and composition of molecules by analyzing the magnetic properties of atomic nuclei.

• NMR spectroscopy involves applying a magnetic field to a sample, which causes the nuclei of certain atoms to resonate at specific frequencies.

• The resulting signals are detected and used to create a spectrum that provides information about the chemical environment of the nuclei.

• N...read more

pH is a measure of acidity or alkalinity of a solution on a scale of 0 to 14.

• pH stands for 'potential of Hydrogen'

• It measures the concentration of hydrogen ions in a solution

• A pH of 7 is considered neutral, below 7 is acidic, and above 7 is alkaline

• Examples: Lemon juice has a pH of around 2, while baking soda has a pH of around 9

Ranges in NMR and UV can be identified by analyzing the chemical shifts and absorption peaks, respectively.

• In NMR, chemical shifts are measured in parts per million (ppm) and can range from 0 to 12 ppm for proton NMR.

• In UV spectroscopy, absorption peaks are observed at specific wavelengths, typically ranging from 200 to 400 nm.

• Interpreting the peaks and shifts in the spectra can help determine the functional groups pre

Silica gel is used as a stationary phase in chromatography due to its high surface area and ability to interact with a wide range of compounds.

• Silica gel has a high surface area, allowing for better separation of compounds based on their interactions with the stationary phase.

• It can interact with a wide range of compounds, making it versatile for different types of chromatography techniques.

• Silica gel is chemically ine...read more

Oxidation is the loss of electrons by a molecule, atom, or ion, while reduction is the gain of electrons.

• Oxidation involves the addition of oxygen or loss of hydrogen, while reduction involves the loss of oxygen or gain of hydrogen.

• Oxidation increases the oxidation state of a molecule, while reduction decreases it.

• An example of oxidation is the rusting of iron, where iron reacts with oxygen to form iron oxide.

• An exampl...read more

Isomerism is a phenomenon in which two or more compounds have the same molecular formula but different structural arrangements.

• Isomers have different physical and chemical properties.

• Types of isomerism include structural isomerism, stereoisomerism, and conformational isomerism.

• Example: Structural isomers - butane and isobutane.

• Example: Stereoisomers - cis and trans isomers of 2-butene.