Chemical analysis Flashcards
What is the difference between a pure substance and a mixture
Pure - a substance which consists of a single element or compound
Mixture - two or more different substances, not chemically bonded
How can you tell the difference between a pure substance and a mixture
A pure substance will have a fixed melting point
A mixture will have a range of melting points
What is a formulation and what are some examples
A mixture that has been designed as a useful product
Fuels
Medicine
Fertiliser
Required practical : Chromatography
What is the method
Pour 1 cm of water into a beaker
Draw a pencil to draw a line 1.5 cm from the bottom of the chromatography paper
Put the solvent on the line using a capillary tube and label it underneath in pencil
Wrap the top of the paper on a splint and hold it together with a paperclip and put into the beaker
Take out the paper once the water reaches ¾ of the paper and let it dry
Required practical : Chromatography
What are the phases
Mobile - solvent moving through the paper, carrying different substances with it
Stationary - contained on the paper and doesn’t move through it
Required practical : Chromatography
How do you calculate the Rf value
Distance travelled by substance / distance travelled by solvent
How do you test for oxygen and what is the expected outcome
Place a glowing splint into the tube
Splint relights
How do you test for hydrogen and what is the expected outcome
Place a burning splint into the tube
Create a pop sound
How do you test for carbon dioxide and what is the expected outcome
Bubble gas through lime water
Lime water will go from clear to cloudy