Purity and Formulations Flashcards
What is a pure substance in chemistry?
Something that only contains one compound or element throughout- not mixed with anything else.
How can you test the purity of a substance?
By measuring its melting of boiling point and comparing it to the melting of boiling point of a pure substance which can be found in a dates book.
The closer your measured value is to the actual melting of boiling point , the pure your sample is.
Impurities in a sample will ——- the boiling point.
Which may result in your sample boiling over range of temperatures
Increase
What are formulations?
Useful mixtures with a precise purpose (like a recipe) each component and their formulation is present in a measured quantity and contributes to the properties of the formulation so that it meets its required function.
What is an example of formulations?
Paint
Name the formulations composed in paint
Pigment- to give the paint colour
Solvent -used to dissolve the other components and alter its runniness
Binder (resin) - forms a film that holds the pigment in place after it’s been painted on
Additives - add further change the physical chemical properties of the paint
Depending on the purpose of the paint, the chemicals used in the amounts will be changed so the paint produced is right for the job .
How may formulations be important in the pharmaceutical industry?
Can alter the formulation of a pill to make sure it’s delivers the drug to the correct part of the body at the right concentration, that it’s consumable and has a long enough shelf life.
Name every day formulations:
Cleaning products, fuels, cosmetics, fertilisers, metal alloys, food and drinks.
How can you test for chlorine gas?
Chlorine bleach is damp litmus paper turning it white
(if you use blue limitless paper and may turn red for moment first, though- that’s because a solution of chlorine is acidic)
Put damp litmus paper in a testing tube and it will turn white if chlorine gases in it
How do you test for oxygen gas?
If you put a glowing splint inside a test tube containing oxygen, the oxygen will relight the glowing splint.
How do you test for carbon dioxide gas?
Bubbling carbon dioxide through (or shaking carbon dioxide with) an aqueous solution of calcium hydroxide (known as lime water)
Will turn the solution to cloudy
(if carbon dioxide is present)
How do you test for hydrogen gas?
If you hold a burning splint at the open end of a test tube containing hydrogen, you’ll get a “ squeaky pop” (the noise comes from the hydrogen burning quickly in the oxygen in the air to form water)
Therefore, hydrogen gas is present if you squeaky pop when you put a lighted splint near the test tube
Paper chromatography practical
Paper chromatography practical, calculating the RF value for each chemical.
Rf = distance travelled by substance/ distance travelled by solvent
