C3 Structure And Bonding Flashcards
How does graphite conduct electricity
Delocalised electrons are free to move through graphite so can carry charges and allow an electrical current to flow
Nanotube
Hollow cylinder of carbon atoms
Relative mass proton neutron electron
Proton = 1
Neutron = 1
Electron = 0
Ion
When number of protons is different to number of electrons
Isotope
Atom of same element with same number of protons but different number of neutrons
Why do solid ionic substances not conduct electricity
Ions are fixed in position and not free to carry charge
Delocalised
Free to move through the whole structure
How are positive metal ions attracted to delocalised electrons
Electrostatic force of attraction
How are pure metals malleable
Layers can slide over each other
4 properties of pure metals
Malleable
High melting boiling points
Good conductors of thermal energy
What did James Chadwick discover
Neutrons
2 properties of nanotubes
High tensile strength
Conduct electricity
How nanoparticles are able to catalyse reactions
The large surface area to volume ratios of nanoparticulate substances allows them to act as catalysts
How a metal and nanoparticles of the same metal can have different properties
The tiny size of nanoparticles compared to the same material in bulk
Why pure water can’t conduct electricity
Does not contain ions
Describe how metals conduct electricity
Due to the metallic bonding
In metallic bonding, the outer electrons are delocalised (free to move)
This produces an electrostatic force of attraction between the positively charged metal ions, and the negatively charged delocalised electrons
What happens when a magnesium atom reacts with an oxygen atom
The magnesium atom loses two electrons to form the Mg2+ cation
The oxygen atom gains these electrons to form the O2– anion
Describe the structure and bonding of diamond
Each carbon atom is joined to four other carbon atoms by strong covalent bonds
Giant covalent structure
The student adds zinc oxide to hydrochloric acid until the zinc oxide is in excess
Give one observation that the student could make to show that the zinc oxide is in excess
Undissolved zinc oxide at the bottom of the reaction container
Why is excess zinc oxide used rather than excess hydrochloric acid?
Zinc oxide is insoluble in water, while hydrochloric acid is soluble
One other compound that the student could add to hydrochloric acid to produce zinc chloride
Zinc sulfate
Explain how these fractions are obtained from crude oil by fractional distillation
Crude oil is separated by fractional distillation
Crude oil is heated to vaporize the different hydrocarbons in a tank which is cool at the top and hot at the bottom
The vapours then rise and the different hydrocarbons condense at their boiling points
Petrol contains a hydrocarbon with the formula C9H20
Complete the equation for the complete combustion of C9H20
C9H20 + 14O2 → 9CO2 + 10H2O
Conditions for cracking
High temperatures typically between 450 C to 750 C
How many outer electrons do noble gases have
8
Except helium has 2
2 C(s) + SiO2(s) → Si(s) + 2 CO(g)
Explain what this reaction shows about the position of silicon in the reactivity series
Carbon is more reactive than silicon
Reactivity series
lists the metals in order of reactivity
From the most reactive at the top potassium to the least reactive at the bottom gold
Top 3 of reactivity series
Potassium
Sodium
Lithium
3 last in reactivity series
Silver
Gold
platinum (lowest)
Why aluminium is more expensive than carbon.
Large amounts of electrical energy used in the extraction process for aluminum
1 observation the student can make to show the zinc oxide is in excess
Solid no longer disappears
Solid remaining
How the student obtains crystals of zinc chloride from a solution of zinc chloride
Heat until crystallisation point is reached
Leave solution to cool
How zinc copper and another substance can be used to light a lamp
Solution in container
Zinc, electrode and copper electrode both inserted into solution
Why rubidium is more reactive than potassium
Rubidium’s outer electron further from nucleus
Less electrostatic attraction between nucleus and outer electron
Outer electron more easily lost
Equation for reaction of rubidium with water
Rb + 2H2O ————-> 2RbOH + H2
Metal react with water
Metal + water ———-> metal hydroxide OH- + hydrogen H2
Noble gases boiling point trend
Increase as go down the group
How alkaline solution is produced
Sodium ions and hydroxide ions are left in solution
Hydrogen ions reduced
Chloride ions oxidised
Why products are difficult to separate if magnesium used to reduce silicon dioxide
Both products are solid
Calculate the minimum mass in grams of magnesium needed to completely reduce
1.2 kg of silicon dioxide.
40 x 24 = 960 grams
