Atom vs Molecule vs Compound - Development of the Periodic Table Flashcards
What is an atom?
The smallest part of an element that can exist
What is a molecule?
Any elements that are chemically combined, even if they are the same element e.g methane, water,ammonia (also compounds)
What is a compound?
2 or more different elements chemically combined in fixed proportion
What’s an element?
Atoms are all the same
How to calculate relative atomic mass?
(% of isotop 1 X mass of isotope 1) + (% of isotop 2 X mass of isotope 2) ÷ 100
What is relative atomic mass?
Average of the mass numbers of the different isotopes
What are isotopes?
Atoms with the same number of protons but different number of neutrons
What is relative atomic mass?
Average of the mass numbers of the different isotopes
What is a mixture?
Different elements or compounds that aren’t chemically combined
What can physical separation techniques only separate?
Mixtures only
What is filteration used for?
To separate an insoluble solid from a liquid
What is crystallisation used for?
To separate a soluble solid from a liquid
What is simple distillation used for?
To separate 2 liquids of different boiling points OR getting a liquid out of a soluble solid
Explain how simple distillation is done
- Evaporate the liquid by heating - turns liquid into a vapour
- Condense vapour by cooling so it become s a liquid
What is fractional distillation used for?
When you want to separate many liquids with different boiling points
Name the apparatus for fractional distillation
- Fractionating column (glass beads rod)
- Thermometer
- Condesor
- Bunsen burner
- Flask
- Beaker
What is the stationary phase in chromotography?
The paper because it doesn’t move
What is the mobile phase in chromotography?
The solvent because it moves
What will a pure compound produce in chromotography compared to a mixture?
A single spot in all solvents whereas a compound in a mixture will separate into different spots
Why do some dots travel further in chromotography?
Its more soluble so its more attracted to the mobile phase
Why do we draw the line with a pencil in chromotography?
The pen ink could dissolve in the solvent and move up the paper
