FREE Master of Chemistry: Analytical Chemistry Questions and Answers

Question 1

The absorption behavior of solutions with concentration is explained by Beer Lambert law.

Accepted Answer

Less than 1 mMol

Answer

The Beer-Lambert Law, which describes the linear relationship between absorbance and concentration, is most accurate for dilute solutions. Deviations from linearity typically occur at higher concentrations, generally above 0.01 M (or 10 mMol), due to factors like intermolecular interactions, changes in refractive index, and scattering effects. Therefore, the law is best applied to solutions with concentrations less than 1 mMol for optimal accuracy.

Question 2

Material for building grating

Accepted Answer

None of these

Answer

Diffraction gratings are typically fabricated by ruling or etching fine, parallel lines onto a highly polished substrate, often made of glass, quartz, or plastic. These lines are frequently coated with a reflective material like aluminum. While fused silica is a type of glass used as a substrate, and plastic gratings exist, none of the options singularly represent the universal or primary material for the *active* grating structure itself, which is often a metallic film. Therefore, 'None of these' is the most appropriate answer given the choices.

Question 3

What amount of solute is needed to prepare 300 ml of 0.8M CaCl2 (mol.wt:111 g/mol)?

Accepted Answer

26.64 g

Answer

First, calculate the moles of CaCl₂ needed: Moles = Molarity × Volume (in Liters) = 0.8 mol/L × 0.300 L = 0.24 moles. Next, convert moles to mass using the molar mass: Mass = Moles × Molar Mass = 0.24 mol × 111 g/mol = 26.64 g. Therefore, 26.64 g of CaCl₂ is required.

Question 4

There are several primary vibrations for linear molecules, including

Accepted Answer

3N-5

Answer

The number of fundamental vibrational modes (normal modes) for a molecule depends on its geometry and the number of atoms (N). For linear molecules, there are 3N - 5 vibrational modes, as two rotational degrees of freedom are removed. For non-linear molecules, the formula is 3N - 6.

Question 5

The output of a photomultiplier tube is in the form of

Accepted Answer

Current

Answer

A photomultiplier tube (PMT) operates by converting incident photons into electrons, which are then amplified through a cascade process involving dynodes. This amplification results in a measurable electrical current at the anode, which is directly proportional to the intensity of the light detected. Thus, the output is in the form of current.

MChem Master of Chemistry Practice Test

MChem Master of Chemistry Practice Test

FREE Master of Chemistry: Analytical Chemistry Questions and Answers