Chemical Structures
C2
- Created by: Belinda
- Created on: 01-06-11 11:06
Covalent Bonds & Covalent structures - simple mole
Covalent bond=very strong bond between non-metals where electrons are shared
A single convalent bond = when two atoms share one pair of electrons, each atom shares one electron in the bond
A double covalent bond = when 2 electrons are shared
A triple covalent bond = When 3 electrons are shared
Examples of covalent compounds: Hydrogen chloride, carbon dioxide, water
Simple covalent structures are molecules with few atoms. they have strong forces between the atoms but weak intermolecular forces
so simple molecules have low melting and boiling points and no overall charge so can't conduct electricity
Covalent molecules can dissolve in non-aqueous solutions
The halogens
They are diatomic molecules (contain 2 atoms which are covalently bonded by a pair of electrons
The attraction between chlorine molecules is weak so melting and boiling points are low. Chlorine = gas at room temp
Attraction between bromines molecules is weak, its melting and boiling points. bromine = liquid at room temp
The intermolecular forces of Iodine are strong. It boils at 184 degrees but still the covalent bonds don't break
Covalent structures - giant molecules & Bonding in
Giant covalent structures have many atoms
Diamond is lattice where each carbon atom forms four bonds, it has high melting and boiling points and can't conduct electricity
Graphite is lattice each carbon atom forms three covalent bonds. It's in a layered structure, the layers slide past each other. It has high melting and boiling points. It can conduct electricity.
Metal atoms form giant crystalline structures. Atoms are packed together tightly so the outer electrons get separated from the atom.
Metals conduct electricity well because the electrons move freely within structure and carry electric the charge
Other carbon structures and uses of carbon structu
Buckminster Fullerenes (bucky balls) = Carbon 60
Properties:
Unsaturated carbon-carbon bonding
Stronger than diamond
Returns to its orginal shape
Spins at high speeds
Not very reactive, can be dissolved
Caron nanotube = half an atom of a buckyball
it is the strongest form of carbon, it is flexible and can bend up or down to contact an electrode
Uses of carbon structures:
conduct electricity
Transistors and diodes
Ion storage for batteries
Reinforcemtn in buildings
Industrial catalysts
Chemical-based therapy & How medicines work
Chemical-based therapy = a form of medication taken to alleviate (relieve) symptons of an illness or ailment E.g:
- Chemotherapy - used to treat cancer and to stop the spreading of cancer, it is very effective
- Antibiotics - used to destroy bacteria
Most medicines replace substances that are deficient or missing in the body
Medicines can alter the activity of cells
They can destroy infectious microorganisms or abnormal cells
Homeopathic Medicine & Argument against Homeopathy
Homeopathic treatments = Medicines that alter the activity of cells
They use weak, diluted doses of compounds or drugs that would cause symptoms of the illness in a healthy person
This causes the body to kickstart the natural healing process
Each homeopathic medicine is tailored to the individual patient
Some scientist believe that homeopathic medicines just have a placebo effect
Homeopathic medicines are inert so have a short term effect on the patient
Some scientists believe that the laws of physics and chemistry would need to be re written in order to make sense of how homeopathy works
Related discussions on The Student Room
- Bonding A level chem - AQA »
- Help urgent spectroscopy »
- Do I need to know how to draw structures for carbohydrates? (AQA A Level Bio) »
- Please help me find marks (2 marks of an A* for A level chemistry) »
- Please help this is due tomorrow »
- AQA GCSE Chemistry Paper 1 Higher Tier Triple (8462 1H) - 17th May 2024 [Exam Chat] »
- What type of isomerism do Ketones and Functional groups have? »
- Alevel Chemistry Aromatic Compounds »
- protein a level biolgy AqA »
- OCR Biology Help: »
Comments
No comments have yet been made