Purity and formulations

Question 1

Define pure substance

Answer 1

• Something that only contains one compound or element throughout - not mixed with anything else

Question 2

When do chemically pure substances boil and melt and how can you test the purity of a sample??

Answer 2

at a specific temperature
- By measuring the samples mp and bp and comparing it with mp and bp of a pure substance

• The closer your measured value to the actual mp and bp, the purer the sample is
• impurities in your sample = lower mp and increase the melting range of your substance

Impurities in your sample will also increase bp and may result in your sample boiling at a range of temperatures

Question 3

What is a formulations

Answer 3

useful mixtures with a precise purpose that are made by following a ‘formula’.Each component in a formulation is present in a measured quantity and contributes to the properties of the formulations so that it meets its required function

Question 4

Example : paint formulations composed of

Answer 4

Pigment: gives paint the colour
Solvent : used to dissolve other compounds and alter the viscosity
Binder : forms a film that holds pigment in place
Additives : added to further change the physical/chemical properties

Question 5

Why are formulations important ?

Answer 5

Pharmaceutical industry for example: altering the formulation of a pill, chemists can make sure it delivers the drug to the correct part of the body at right concentrations, that its consumable and has a long enough shelf life.

In everyday life, formulations can be found in cleaning products, fuels, cosmetics, fertilisers, metal alloys and even food/drinks

When you buy a product, you might find that it has information about its composition on the packaging - tells you the product formulation and lets you pick and choose a formulation with the right composition for your particular use