Gravimetric Analysis

Question 1

What is gravimetric analysis?

Answer 1

Analytical determination of the mass of an element or compound in a substance by chemically changing the substance

Question 2

Describe gravimetric analysis.

Answer 2

Gravimetric analysis is used to determine the mass of an element or compound in a substance. The substance is converted into a product of known chemical composition, which can be readily isolated and purified. The conversion can either occur through precipitation or volatilisation.

Question 3

Describe gravimetric analysis through precipitation reaction.

Answer 3

In precipitation conversion the substance undergoes a precipitation reaction. The precipitate is then separated from the filtrate and the filtrate tested to ensure the reaction has gone to completion. The precipitate is washed, dried and then weighed.

Question 4

Describe gravimetric analysis through volatilisation reaction.

Answer 4

In volatilisation conversion the substance is heated and any volatile products are driven off. It is heated to constant mass and the final mass recorded.

Question 5

What is meant by heating to a constant mass?

Answer 5

Substance heated and weighed. This is repeated until the mass remains constant.

Question 6

What is the purpose of a desiccator?

Answer 6

To stop water getting in and prevent moisture absorption.

Question 7

What is meant by ‘weighing approximately accurately’?

Answer 7

the measured value doesn’t need to be exactly the theoretical value. However, the value measured has to be accurate.