C5 - Chemicals in the Natural Environment (OCR 21st Century)

?
What is ionic bonding?
Giving or taking electrons to form ions.
1 of 52
What is the hydrosphere?
A sphere of the Earth containing the sea, oceans, rivers; places where water is found
2 of 52
Sodium chloride formula? Note that the (+) represents charge.
Na(+)Cl(-) forms NaCl
3 of 52
Magnesium Sulfate formula?
Mg(2+)SO4(2-) MgSO4
4 of 52
Magnesium Chloride formula?
Mg(2+)Cl(-) forms MgCl2
5 of 52
Potassium Chloride formula?
K(+)Cl(-) forms KCl
6 of 52
Potassium Bromide?
K(+)Br(-) forms KBr
7 of 52
Sodium Sulfate?
Na(+)SO4(2-) forms Na2SO4
8 of 52
Why do tests to locate ions work?
Ions have distinct properties, and the compounds they form also have distinct properties, so it's easy to detect them.
9 of 52
Positive ions are...
Metals
10 of 52
Negative ions are...
Non-metals
11 of 52
What happens when you add NaOH to a metal?
It forms a metal hydroxide.
12 of 52
What is the significance of this reaction resulting in an insoluble hydroxide?
It will form a coloured precipitate; the colour of which can tell you about which ions are present in it.
13 of 52
Give an example of a reagant that can react with non-metals.
Silver nitrate
14 of 52
What does the reaction between a non-metal and a reagant result? What does this tell us about which ions are present?
It forms another solid coloured precipiate, which tells us which ions are present in the reaction.
15 of 52
What feature of a dot and cross diagram shows you that it portrays ionic bonding?
The square brackets around the elements.
16 of 52
What does the ionic bonding of sodium and chlorine result in? Why?
An electrostatic force between them, as sodium is positively charged, and the electron that it shared with chlorine is negatively charged.
17 of 52
What are ionic bonds? What force does it utilise?
Two forces of attraction between oppositely charged ions. The force is known as an electrostatic force.
18 of 52
How is a giant ionic lattice formed?
Multiple ions with opposing forces are joined with electrostatic forces
19 of 52
How is it giant?
It occurs many times.
20 of 52
How is it a lattice?
It is a regular formation.
21 of 52
What happens when you apply force to an ionic lattice?
The lattice structure shifts; you'll get two of the same element next to each other, which repels and shatters the crystal.
22 of 52
What is the boiling point, conductivity and melting point of a giant ionic structure?
High boiling point because it's hard to break the 6 bonds between each ion, does not conduct when solid because there are no free electrons present, high melting point.
23 of 52
What happens when ions are dissolved?
They dissociate/separate.
24 of 52
Why does this happen?
Water molecules have a very small charge, which surrounds the ions and prevents them from reforming.
25 of 52
What is (aq)?
Aqueous; a dissolved solution.
26 of 52
Give an example of a simple covalent bond.
The double bonds between oxygen molecules, which have very weak intermolecular forces.
27 of 52
What is an intra-molecular bond?
The bond within a molecule.
28 of 52
What is the intra-molecular bond like within an oxygen molecule?
Very strong.
29 of 52
What are the features of simple covalent bonds?
In gases, they are very easily broken at a low temperature.
30 of 52
What is the structure of a nitrogen atom? What is the significance of this structure in covalent bonding?
Triple bonded, meaning that there are three pairs of electrons that are shared to form a complete shell.
31 of 52
Define covalent bonding.
Electrostatic attraction between protons and electrons, often between two non-metals.
32 of 52
Why do covalent structures not conduct (when pure)?
They have no charge; when they bond, the charges cancel each other out.
33 of 52
What is the lithosphere?
The structure of the Earth (core, outer core, mantle, crust).
34 of 52
Where in the lithosphere are minerals most commonly formed?
The crust.
35 of 52
What is the significance of diamond's tetrahedral structure?
High boiling point, high melting point (many bonds), insoluble (no ions), hard, doesn't conduct.
36 of 52
Why does graphite have a high boiling and melting point?
Very strong covalent bonds between the carbon atoms.
37 of 52
How does graphite conduct electricity?
It has layers with free electrons between them; unlike diamond, which has none.
38 of 52
Why is it easy to separate the layers between graphite?
Because while the intramolecular bonds are strong, the intermolecular bonds are veyr weak.
39 of 52
Do giant structures have weak metallic bonds?
Nah
40 of 52
Why are the metallic bonds strong?
Because between the positively charged metal ions is a 'sea' of delocalized/free electrons. These are electrostatic-ally attracted to each other.
41 of 52
What part of a metallic bond allows for conductivity?
The free electrons, which allow charges to flow through them without an issue.
42 of 52
What happens when you apply force to a giant metallic structure?
The ions can 'slip over each other' and free the electrons further, making the metal bendable/malleable.
43 of 52
Why do we do electrolysis?
Aluminium is too reactive to reduce.
44 of 52
Describe the structure of an electrolysis tank.
The tank has positive electrode (anodes) rods, and negatively charged electrodes around the edges.
45 of 52
Why is aluminium dissolved in cryolite?
To melt it, a temperature of around 2000 degrees celcius is needed; but with molten cryolite, it easily dissolves in half the temperature, making it much cheaper than melting.
46 of 52
Describe the process of electrolysis.
Aluminium is dissolved in cryolite, then poured into the tank, where the oxygen ions are attracted to the negative cathodes, and the aluminium ions are attracted to the anode rods.
47 of 52
What is the number of ions equivalent to in the periodic table?
Group number.
48 of 52
What happens to the oxygen at the cathode?
It is oxidised, and reacts with the graphite to create carbon dioxide.
49 of 52
What happens to the aluminium at the anode?
It is reduced, resulting in an aluminium atom that can be extracted.
50 of 52
What are the downsides to electrolysis?
The anodes need to be replaced regularly; carbon dioxide is the waste product/contributes to global warming.
51 of 52
What are the properties of metals?
Malleable, high melting point, conduct electricity, strong.
52 of 52

Other cards in this set

Card 2

Front

What is the hydrosphere?

Back

A sphere of the Earth containing the sea, oceans, rivers; places where water is found

Card 3

Front

Sodium chloride formula? Note that the (+) represents charge.

Back

Preview of the front of card 3

Card 4

Front

Magnesium Sulfate formula?

Back

Preview of the front of card 4

Card 5

Front

Magnesium Chloride formula?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Ionic Bonding resources »