Chemistry OCR, C5

HideShow resource information
What gases make up our surrounding air?
78% nitrogen, 21% oxygen, 1% argon and 0.04% carbon dioxide
1 of 42
What melting and boiling points do molecular elements and compounds with small molecules have?
low melting and boiling points
2 of 42
What are the properties of molecular elements and compounds in the air?
have low melting and boiling points and are gases at room temperature because they consist of small molecules with weak forces of attraction between the molecules
3 of 42
Why don't pure molecular compounds conduct electricity?
because their molecules aren't charged
4 of 42
What type of bonding is there within molecules?
bonding within molecules is covalent and arises from the electrostatic attraction between the nuclei of the atoms and the electrons shared between them
5 of 42
What is the difference between the bonds within the molecules and the forces of attraction between small covalent molecules?
the bonds within molecules are covalent bonds, which are strong, in contrast to the weak forces of attraction between small covalent molecules
6 of 42
What does the Earth's hydrosphere (oceans, seas, lakes and rivers) mainly consist of?
consists mainly of water with some dissolved compounds of salts
7 of 42
How are ions in crystals of a solid ionic compound arranged?
arranged in a regular way, forming a lattice
8 of 42
What is ionic bonding?
when ions in a crystal are held together by forces of attraction between oppositely charged ions
9 of 42
What are the physical properties of an ionic compound?
high melting and boiling points because the ions are held together by strong forces of attraction in a lattice, don't conduct electricity when solid because ions are fixed in place and can't move, conduct electricity when molten/dissolved
10 of 42
What happens to the ions when an ionic crystal dissolves in water?
ionic compounds dissolve in water because water molecules are polar. A water molecule is attracted to an ion in the crystal lattice, ion breaks away from the lattice and moves freely through the water
11 of 42
Why do ionic compounds conduct electricity in water?
the ions are charged and are able to move independently in the solution
12 of 42
Why can ions in an ionic compound be detected and identified?
they have distinct properties and they form compounds
13 of 42
What are insoluble compounds in a mix of two solutions of ionic compounds called?
precipitates
14 of 42
How can some metal ions be identified in solution?
by adding alkali because they form insoluble hydroxides with characteristic colours
15 of 42
How can some negative ions in salts be identified?
by adding a reagent that reacts with the ions to form an insoluble solid
16 of 42
What is the Earth's lithosphere?
the rigid outer layer of the Earth made up of the crust and the part of the mantle just below it and is made up of a mixture of minerals
17 of 42
What are diamond and graphite molecules composed of?
carbon atoms
18 of 42
What are the properties of diamond?
diamond is very hard because each carbon atom is covalently bonded to four other carbon atoms, the covalent bonds are strong and so has a high melting point and is insoluble in water
19 of 42
What are the properties of graphite?
graphite is soft and can conduct electricity because each carbon atom is covalently bonded to three other atoms and are arranged in sheets that can slide over each other. Spare electrons can move between the layers high melting point and insoluble
20 of 42
What are other very abundant elements in the Earth's crust?
silicone, oxygen and aluminium. Silicone and oxygen are present in the Earth's crust as the compound silicone dioxide
21 of 42
Why does silicone dioxide have properties similar to diamond?
silicone is another giant covalent compound
22 of 42
What are ores?
rocks that contain varying amounts of minerals from which metals can be extracted
23 of 42
How can zinc, iron and copper be extracted?
by heating their oxides with carbon. Metal oxide is reduced and carbon is oxidised
24 of 42
Why can't some metal oxides be reduced by carbon?
they are too reactive
25 of 42
Where can relative atomic masses be found?
on the periodic table
26 of 42
How can you calculate the relative formula of mass?
add up all the relative atomic masses
27 of 42
How can you calculate the mass of the meta that can be extracted from a mineral?
work out the relative formula mass, work out the percentage mass of the metal and work out mass of the metal
28 of 42
What is electrolysis?
the decomposition of an electrolyte with an electric current
29 of 42
What happens to the ions when an ionic crystal melts?
electrostatic forces between the charged ions in the crystal lattice are broken down and the ions are free to move
30 of 42
During electrolysis, what forms at the negative electrode and what forms at the positive electrode?
metals form at the negative electrode and non-metals form at the positive electrode
31 of 42
How is aluminium extracted from aluminium oxide by electrolysis?
aluminium ore is purified to leave aluminium oxide, it is then mixed with cryolite to lower its melting point. New mixture is melted so ions can move, when a current passes through the molten mixture positive aluminium is formed at negative electrode
32 of 42
During aluminium electrolysis, why is aluminium formed at the negative electrode?
when a current passes through the molten mixture, positively charged ions move towards the negative electrode, where aluminium is formed. Negatively charged oxide ions move towards the positive electrode, where oxygen is formed
33 of 42
During aluminium electrolysis, why are neutral atoms formed?
positively charged aluminium ions gain electrons from the negative electrode, to become neutral and negatively charged oxide ions lose electrons to the positive electrode to become neutral atoms which then combine to form oxygen molecules
34 of 42
What happens to ions when they get to the oppositely charged electrode?
they're discharged, they lose their charge
35 of 42
What is metallic bonding?
the strong forces of attraction that hold a metal's giant structure of ions together?
36 of 42
Why are metals strong?
the ions are closely packed in a lattice structure
37 of 42
Why do metals have high melting points?
a lot of energy is needed to break the strong metallic bonds
38 of 42
Why are metals malleable?
the layers of metal ions can slide over each other
39 of 42
Why can metals conduct electricity?
electrons are free to move throughout the structure. When a voltage is applied, the electrons move through the metal is one direction
40 of 42
What can be used to describe the physical properties of metals, including malleability and conductivity?
in a metal crystal, there are positively charged ions, held closely together by a sea of electrons that are free to move
41 of 42
What are environmental impacts of metal extraction?
air/noise pollution, pollutants caused by transport, energy usage, landfill sites reduce natural wildlife, lots of rock wasted and leaves scar on landscape
42 of 42

Other cards in this set

Card 2

Front

What melting and boiling points do molecular elements and compounds with small molecules have?

Back

low melting and boiling points

Card 3

Front

What are the properties of molecular elements and compounds in the air?

Back

Preview of the front of card 3

Card 4

Front

Why don't pure molecular compounds conduct electricity?

Back

Preview of the front of card 4

Card 5

Front

What type of bonding is there within molecules?

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 C5 resources »