Chapter C3 Structure And Bonding Flashcards
What’s the the states of matter?
Solid
Liquid
Gas
Properties of a solid
Fixed shape and volume
Cannot be compressed
Properties of a liquid
Liquids have a fixed volume but can flow and change their shape
Cannot be compressed
Properties of gases
Gases have no fixed shape or volume
Can be easily compressed
What is the pressure from a gas caused by?
Particles colliding with the edge of the container
How does a solid go to liquid?
Melting
How does a liquid go to a solid?
Freezing
How does a liquid go to a gas?
Evaporation
How does a gas go to a liquid?
Condensation
How does a gas go to A solid?
Sublimation
Why is there a change of state during melting?
The vibrations between the particles will be sos trying that they will break apart and gain a freer structure
Does anything change with change of state?
No
An ice cube is the same as water or water vapour
Why does the temperature stop rising when the object melts?
As energy is transferred from the surroundings to the forces between particles within the solid, forcing them to break. Once fully melted, the transfer of energy will be towards the substance causing the temperature to continue rising
What is covalent bonding?
Sharing electrons
What is ionic bonding?
Transferring electrons
Why will an element in the alkali metals becoming a positive ion?
As there will be more protons in the nucleus than electrons in the electron shells, thus there will be a positive charge
Why will ana element in the halogens become a negatively charged ion?
As they will gain an electron, meaning their nucleus has less protons than the electron shells, and so it is negatively charged
How is ionic bonding displayed?
Dot and cross diagrams
What is a giant lattice?
A 3D network of ions or atoms
What happens to the charge if the ion when group two ionically bonds?
It gains a plus two charge
When drawing complete ionic bonds, what do you add?
Brackets displaying the charge
Why do ionic compounds have high melting points?
As you must overcome the forces of electrostatic attraction
Properties of an ionic solid
Ions are in fixed position and can only vibrate
Do not conduct electricity
Properties of a molten ionic compound
High temperature provides enough energy to overcome the many strong forces between ions- free to move within molten compound
Conducts electricity
Properties of an ionic compound in solution
Water molecules separate ions from the lattice- ions are free to move in solution
Does not conduct electricity
What is a double bond?
Two pairs of electrons are shared
What are intermolecular forces?
The attraction between individual molecules in a covalent bonded substance
What increases intermolecular forces?
The size of the molecules
What is a polymer?
Small reactive molecules in very large chains
What are intermolecular forces like on polymers?
Relatively high
Explain how a polymer chain is shown
H H H | | | C-C-C | | | H H H
How many bonds does diamond have?
4 carbon bonds
How many bonds does graphene haven
3 bonds
Properties of diamond
High melting and boiling points
Hard
Insoluble in water
Does not conduct electricity
Properties of graphite
Soft
Can conduct electricity due to the presence of a delocalised electron
Insoluble in water
Why is there a delocalised electron in graphite?
As carbon has four electrons on its outer shell, when the covalent body of graphite is made (which only uses three covalent carbon bonds), there is one electron spare that can conduct electricity
What is a fullerene?
Form of the element carbon that can exist as a large cage like structure, based on hexagonal rings of carbon atoms like graphite, however they may also have rings if five or seven
What are carbon nanotubes?
Cylindrical fullerenes
Properties of carbon nanotubes
High tensile strength
High electrical conductivity and thermal conductivity - they have a delocalised electron
How can fullerenes be used?
Drug delivery into the body- for example to cancer cells at very specific sites within the body
They can be used as lubricants (as can graphite)
They can be used as catalysts due to their large surface area to volume ratio of their nanoparticles
What is graphene?
A single sheet of carbon atoms- just one atom thick
Properties of graphene?
Excellent conductor of electricity (better than graphite)
Has a low density
Most reactive form of carbon
Incredibly strong for its mass
What is a metal lattice?
A lattice of positivity charged ions. They are layered on top of each other. The outer electrons cause a sea of delocalised electrons- this makes metal a good conductor
What are the atoms in mental like?
In a regular pattern in layers
Why can metals be hammered and bent into different shapes?
As the layers of atoms in pure metal can slide easily over each other
What is an alloy?
A mixture of two or more elements at least one that is a metal
Why do metals have high melting points?
The electrostatic forces extend in all directions- this it takes a lot of energy to break the lattice and melt the metal
What does nano mean?
One billionth
Are nanoparticles visible in light?
No they are invisible
What does the surface area to volume ratio show?
The higher the ratio, the higher the proportion of particles exposed at the surface
Why are nanoparticles sustainable?
As less resources are used up
What are concerns of nanoparticles?
Their environmental impact
What are uses of nanoparticles?
Glass can be coated- this means when it rains the water spreads evenly over the surface of the glass washing off the broken down dirt
Modern sunscreens- to make the mixture thicker, this ales them more effective at blocking the suns rays
The cosmetics industry- nanoparticles in face creams are absorbed deeper into the skin
Used in deodorants
How are nanoparticles used in medicine?
Gold nanoparticles can be injected into the body and absorbed by tumours. Tumours have leaky blood vessels with holes hat the nanoparticles can get through- healthy cells do not. Then a laser is directed at the tumour heating up the nanoparticles. This can change the properties of the tumour and destroy the cells, without harming healthy cells
How are nanotubes potentially being used in the future?
To develop nanowire that could make tiny circuits.
Nanotechnology suits as well- can withstand bullets but are flexible
Risks of nanoparticles?
Their large surface area means if one is set off, there could be a large explosion
May find their way into atmosphere, causing damage if breathed in.
Not much research on nanoparticles
