C5 Flashcards
What does dry air contain?
non-metal elements e.g nitrogen, oxygen and argon. Also contains small amounds of non-metal compounds
Molecules can be shown in 2D and…
3D.
What are atoms in molecules held together by?
Covalent bonds
How do covalent bonds form?
When atoms share a pair of electrons.
Why are atoms held together?
Because the positively charged nuclei of both atoms are attracted to the negatively charged pair of electrons.
What is metallic bonding?
Where there are sheets of positively charged metal ions held together by a ‘sea’ of electrons that are free to move,
What does it mean when electrons are free?
they can conduct electricity
Why are metals malleable?
Because the sheets can be pushed passed each other.
Why do metals have high strength and high melting points?
They have a giant structure held together by strong metallic bonds.
What does high strength and high melting points result in?
having various uses such as wiring pipes and bridges.
What is the hydrosphere?
oceans, seas, lakes and rivers- mainly consisting of water with some dissolved compounds, called salts.
How are salts in the hydrosphere formed?
oppositely charged ions which are attracted together forming an ionic bond.
What do oppositely charged ions form? Do they conduct electricity and why?
an ion lattice. It does not conduct electricity because as a solid as the ions cant move.
What do large numbers of strong ionic bonds mean?
Ionic compounds have high melting/boiling points.
Are all ionic compounds soluble?
No
What is the lithosphere?
The crust and the upper parts of the mantle.
What is it made up of?
a mixture of minerals.
Silicon, oxygen and aluminium are…
very abundant elements in the Earth’s crust as aluminium oxide and silicon dioxide.
What are silicon dioxide and diamond?
Giant covalent structures.
What do Giant covalent structures mean?
They have lots of strong covalent bonds holding the structure together and so have high boiling/melting points, don’t conduct electricity and are hard and insoluble.
What is graphite made out of?
Sheets of carbon which can slide past each other, making it soft.
There are electrons between the carbon sheets in Graphite that makes it…
able to conduct electricity.
How can the formula of salt be found and what is the overall charge?
They can be found using the charges of the ions. The overall charge is always 0.
If two solutions are mixed together and an insoluble salt forms what will it be seen as?
A precipitate.
What do insoluble salts have? What does this mean?
distinctive colours, which means that they can be identified by the precipitates that form when they react with certain chemicals.
What do the compounds in air have?
small melting and boiling points as they have weak intermolecular forces between molecules.
At room temperature there is…
Enough energy to break these forces and turn them into gases.
What do the compounds in the atmosphere have holding them together?
Covalent bonds.
The forces between the chemicals of the natural environment are…
weak but the covalent bonds holding the molecule together are very strong.
Why don’t the molecules conduct electricity?
Because they are not charged.
What is the lithosphere made from?
The crust and the part of the mantle just below it.
What are diamond and graphite formed from?
pure carbon that is found in the lithosphere.
Why are diamonds so hard?
Each carbon atom is covalently bonded to four other carbon atoms.
Why is graphite soft?
In granite, each carbon atom is covalently bonded to…four other carbon atoms that are arranged in sheets that can slide over eachother.
In graphite, what can spare electrons do? What does this mean?
move between layers of atoms, which means it can conduct electricity.
In both graphite and diamond, the covalent bonds are…
strong so they have high melting points and are insoluble in water.
How is the silicon and oxygen present in the lithosphere?
As the compound- Silicon Dioxide (SiO2)
Silicon Dioxide is a…
giant covalent structure, so it has similar properties to diamond.
What properties does Silicon Dioxide have?
Hard, High ,MP, insoluble in water and electrical insulator.
Why is sea water in the hydrosphere salty?
Because it contains dissolved ionic compounds called salts.
Sodium is an ionic compound made from…
Positive sodium ions and negative chlorine ions.
Why do ions form a giant 3D crystal lattice? What properties does it have?
Because it has positive sodium ions and negative chlorine ions.The ions are electrostatically attracted to each other to form a giant 3D lattice with high melting and boiling points.
Name some properties of ionic compounds.
High melting points and they don’t conduct electricity when solid, molten or dissolved.
What were the chemists explanation of the structure of ionic compounds explaining these properties? (3).
-They have high melting and boiling points because they have ions held together by strong forces of attraction in a lattice. -They don’t conduct electricity when solid because the ions are fixed in place and can’t move. -They conduct electricity when molten (or dissolved) because the ions are free to move.
Why do most ionic compounds dissolve in water?
Because the water molecules are polar (have a positive and negative end).
Steps of an ionic compound dissolving in water?
- A water molecule is attracted to an ion in the crystal lattice. 2. An ion breaks away from the lattice. 3. The ion moves through the water.
What is meant by the term ‘hydrosphere’?
The water compounds on the Earth
State 2 properties of diamond.
Hard and has a high MP.
State two properties of ionic compounds?
Don’t conduct electricity when solid and have a high melting/boiling point.
In the ocean, calcium ions combine with 1.____to form 2._______.
1.Carbonate ions 2. an insoluble ionic compound (Calcium Carbonate or limestone.
What are solids formed in these types of reactions in oceans called?
Participates.
What can we use precipitation reactions to detect….
ions in aqueous solutions,
We can make predictions about precipitation reactions by…
interpreting information on solubility.
How can positive ions be identified in solution?
By adding sodium hydroxide solution and identifying the colour of the precipitate.
Cu^2+ 20H^- =_____
Cu(OH) ^2
Many negative (non metal) ions can be identified in solution because…
they will react with other aqueous ions to produce an insoluble precipitate.
Ag(aq) + Cl(aq) —–>
AgCl(s)
What are ores?
Rocks that contain varying amounts of minerals from which metals can be extracted.
What does the method of extraction depend on?
How reactive the metal is
What metals can be extracted from their oxides by heating with Carbon?
Metals that are less reactive than Carbon, for example,
What happens when metals are extracted from their oxides by heating with Carbon?
-The metal oxide is reduced as it has lost Oxygen. -The Carbon is oxidised as it has gained Oxygen.
What happens to Zinc when it is extracted from its oxides by heating with Carbon?
Zinc + Oxide Carbon ——> Zinc +Carbon Dioxide
The relative formula mass tells you…
the total mass of atoms in a compound.
How do you work out the relative formula mass in an atom?
Add up the relative atomic masses.
How do you calculate a metals mass?(4)
- Write down the formula 2.Work out the RFM. (Relative Formula Mass) 3.Work out the percentage mass of the metal 4.Work out the mass of the metal
What is electrolysis?
the breaking down of an electrolyte using an electric current.
What is electrolysis used for?
To extract reactive metals from their ores because their too reactive to be extracted by heating Carbon.
Ionic compounds conduct electricity when they’re…
-molten -dissolved in solution.
Why do Ionic compounds conduct electricity?
Because their ions are free to move through the liquid.
What happens when an ionic compound melts?
Electrostatic forces between the charged ions in the crystal lattice are broken down and the ions are free to move.
What happens when a direct current is passed through a molten ionic compound…
-positively charged ions are attracted towards the negative electrode. -negatively charged particles are attracted to the positive electrode.
What happens in the electrolysis of molten lead Bromide?
-positively charged lead ions are attracted to the negative electrode, forming lead. -Negatively charged bromide particles are attracted towards the positive electrode, forming bromine (a non metal).
What happens when ions get to the oppositely charged electrode?
they’re discarded (lose their charge).
What is the environmental impacts of mining?
-lots of rock wasted -leaves a scar on the landscape -air/noise pollution
What is the environmental impacts of processing?
-pollution caused by transportation -Energy usage -Electrolysis uses more energy than reduction
What is the environmental impacts of manufacturing metal products?
-energy usage in processing and transportation.
What is the environmental impacts of transporting the shops or running the product?
-pollutants caused by transportation -energy usage.
What is the environmental impacts of the disposal of a product? (reuse, recycle and throw away) -3.
Reuse- no impact Recycle- uses a lot less energy than the initial manufacturing. Throw away- landfill sites remove wildlife habitats and are eyesore.
A metal has a giant structure of (1)______, that is held together by a (2)_______ called the metallic bond.
- ions. 2. strong force of attraction.
Metals are…
-Malleable -Conductors of electricity- ions are free to move through the structure when a voltage is applied.
In a metal compound, the positively charged metal ions are held together by…
a ‘sea’ of electrons.
State one property and use of Titanium.
Strong- used for replacement hip joints and submarines.
State one property and use of Aluminium.
Malleable- used for drinks cans.
State one property and use of Iron.
High melting point- used for making saucepans.
State one property and use of Copper.
Excellent conductor of electricity- used for cables and electrical switches.
