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level: Textbook - questions

Questions and Answers List

level questions: Textbook - questions

QuestionAnswer
Properties of nanotubesHigh electrical conductivity along the long axis of the cylinder ~some of the electrons are delocalised and are able to move along cylinder when voltage is applied High tensile strength when force is applied along the long axis of the cylinder
Properties of nanotubesHigh electrical conductivity along the long axis of the cylinder ~some of the electrons are delocalised and are able to move along cylinder when voltage is applied High tensile strength when force is applied along the long axis of the cylinder
How do you change *C into kelvinTo change *C to kelvin, add 273 to the Celsius temperature
How do you change the pressure of 1 atmosphere into pascals?A pressure of 101 325 pascals = 1.0 atmosphere pressure
What happened to the particles of a liquid when it cools?- they lose kinetic energy, so they do not move around as readily - Experience increasing forces of attraction - Stop sliding past each other when temperatures is sufficiently low, the liquid solidifies
What happened when we heat a liquid (vaporisation)?- energy transferred makes liquid particles move faster - Forces of attraction weaken - Highest energy particles escape first - Liquid starts to evaporate - Forces weaken further - particles move faster and spread - Liquid Boils
What happened to the particles when we cool a vapour (condesation)- Lose kinetic energy, so molecules move around less quickly - Experience increasing forces of attraction - Move more slowly and become closer together when temperature is sufficiently low, gas liquefies
Define Boiling pointExact definition is the temperatures at which the vapour pressure is equal to the atmospheric pressure
The properties of ionic compounds reflect their structure as well as their bonding:- Hard - Brittle - High melting and boiling points - Many are soluble in water because they can form ion-dipole bonds - Only conduct electricity when molten or in a solution
Define alloyAn alloy is a mixture of two or more metals or a metal and a nonmetal
Some covalently bonded structures have a three-dimensional network of covalent bonds throughout the whole structure. What d we call this structureGiant molecular structures of giant covalent structures
Define allotropesDifferent crystalline or molecular forms of the same element. Term only applies to solids
Properties of graphite related to its structure- High melting and boiling points ~ Strong covalent bonding throughout whole structure - Softness ~ Easily scratched, forces between layers of carbon atoms are weak - Good conductor of electricity ~ When voltage is applied, delocalised electrons can move along the layers
Properties of diamond related to its structureHigh melting and boiling points ~ Strong covalent bonding throughout whole structure Hardness ~It is difficult to break the 3D network of strong covalent bonds Does not conduct electricity ~All 4 outer electrons on every carbon atom are involved in covalent bonding
The individual particles in fullerenes may have one of their dementions between 0.1 and 100 nanometers (1 nanometer = 10^-9m ) Particles of this size is callednanoparticles
Properties of buckminsterfullereneLow sublimation point ~ Turn directly from solid to vapour when heated to about 600*C Soft ~ Does not require much energy to overcome weak intermolecular forces Poor conductor of electricity ~ the extent of electron delocalisation is lower Slightly soluble in solvents such as carbon disulfide and methylbenzene More reactive than graphite or diamond ~reacts with hydrogen, fluorine, chlorine, bromine and oxygen, due to relatively high electron density in certain parts of molecule
Properties of nanotubesHigh electrical conductivity along the long axis of the cylinder ~some of the electrons are delocalised and are able to move along cylinder when voltage is applied High tensile strength when force is applied along the long axis of the cylinder High melting points (±3500*C) ~ because there is strong covalent bonding throughout the structure
Properties of GrapheneMost chemically reactive form of carbon Single sheet of graphene burn at very low temperature and are much more reactive than graphite Graphene is extremely strong for its mass Given amount of material, graphene conducts electricity and heat much better than graphite.