1 Elements, Compounds and Mixtures Flashcards
What is an element?
Substances that can’t be split into anything simpler by chemical means. It contains only one type of atom.
What is a compound?
When two or more elements are chemically combined and are always in fixed proportion.
How do we seperate the elements in a compound?
With a chemical reaction.
What is a mixture?
Different elements or compounds not chemically combined together.
How can mixtures be seperated?
By physical means.
What kind of things melt and boil at a fixed temperature?
- Pure substances
- Elements
- Pure compounds
What happens to the melting and boiling point of mixtures?
They melt and boil over a range of temperatures.
How does the presence of impurities affect the melting and boiling points?
- They lower the melting point
- They raise the boiling point
What are physical separation techniques used for?
To separate mixtures.
What are the separation techniques used for?
- Simple distillation
- Fractional distillation
- Filtration
- Crystallisation
- Paper chromatography
What does insoluble mean?
That the solid won’t dissolve in a liquid.
What does soluble mean?
That the solid will dissolve in a liquid.
What is an aqueous solution?
It means that the substance is dissolved in water.
What is filtration?
It is used to separate an insoluble solid from a liquid.
What is the residue?
The substance left in the filter paper.
What is the filtrate?
The liquid that comes through.
What is an example of the substances that could be used in filtration?
Silver chloride (AgCI) and water (H2O).