Quiz on Pretreatment Operations

The set of operations that are carried out when receiving a sample in the laboratory is called ___________________.

• homogenization

• sampling analysis

• pre-treatment operations

• post-treatment steps

What is the main objective of pretreatment operations in sample analysis?

• To increase the size of the sample

• To provide adequate subsamples for analysis

• To discard unnecessary materials

• To speed up the analysis process

Which of the following is NOT a basic laboratory operation used in sample preparation?

• Grinding

• Sieving

• Dissolving

• Heating

The SAMPLE must be _______________ and ______________.

• representative and heterogeneous

• small amount and homogeneous

• representative and homogeneous

• large amount and hetergeneous

The first task of the sampler is to process the sample. The following are part of processing EXCEPT:

• placing the sample in the most appropriate container

• labelling the container

• writing down the collector's name

• adding distilled water to the sample to avoid contamination

What is the first pre-treatment operation usually performed on solid samples?

• Mixing

• Disintegration

• Grinding

• Sieving

Is reducing the size of the sample of particles the same with reducing the sample size?

• Yes

• No

• Maybe

• Possible

The following are the four different types of solid breakage in milling or crushing apparatus EXCEPT:

• Impact

• Friction or Rubbing

• Convection

• Cleavage or shearing

Answer explanation

It is not convection but compression (coarse reduction of hard solids)

The following are the Grinding classification according to the size obtained EXCEPT:

• Fine ground = 50 microgram

• Ultrafine ground = 10 microgram

• Medium ground = 100 microgram

• Coarse ground = 1 mm

Which material is commonly used for the final stage with low sample volume?

• crushers

• mills

• mortars

• primary mills