Chapter 12 - Chemical Analysis Flashcards
what is meant by purity in chemistry?
A pure substance is one that is made up of just one substance. The substance can be either an element or a compound
what is meant by purity in everyday terms?
‘has nothing added to it’ and it is in its natural state
what are fixed points
The melting and boiling points of an element or a compound
how can you identity a pure substance
it has a fixed point
how can you identify a mixture
it doesn’t have a fixed point. the melting and boiling point of the mixture varies.
define formulation
a mixture with components in fixed ratios that has been designed as a product
give 3 examples of everyday formulations
mixed paints, cakes, medicine
how to calculate the Rf value
Rf = distance moved by the substance/distance moved by the solvent
give an example of a mobile phase in chromatography
water (solvent)
give an example of a stationary phase in chromatography
paper
what is the test for hydrogen
a lit split —-> squeaky pop
what is the test for oxygen
a glowing splint —-> relights in the presence of oxygen
what is the test for chlorine
damp blue litmus paper —–> bleaches white
what is the test for carbon dioxide
limewater —–> turns cloudy
2 ways to test for positive ions
flame tests and adding sodium hydroxide
