chemistry 21-30 Flashcards
1
Q
- How does filtration work?
A
Separates an insoluble substance in the solid state from substances in a liquid state (fig 1)
2
Q
- How does crystallisation work?
A
Evaporating the solvent of a solution leaving the solute behind (fig 2)
3
Q
- How does simple distillation work?
A
Separates a solvent from a solution. (fig 3)
4
Q
- What are the two stages of chromatography?
A
Stationary phase – does not move, absorbent paper/TLC plate
Mobile phase – solvent in liquid phase e.g. water, propanone
5
Q
- How do you calculate the Rf value?
A
Rf = distance travelled by substance
distance travelled by solvent
6
Q
- How many electrons can go in the first, second and third shells?
A
2.8.8
7
Q
- What can the group tell you about the electrons in an atom?
A
How many electrons in the outer shell. E.g. carbon is in group 4 so has 4 electrons in the outer shell
8
Q
- What can the period tell you about the electrons in an atom?
A
How many shells an atom has. E.g. carbon is in the second period so has two shells
9
Q
- Why did Mendeleev put some elements in groups?
A
Because they had similar chemical properties (e.g. they reacted violently with water)
10
Q
- What type of bonding is this? (ionic)
A
ionic
