Atomic Structure
Balance the following equation:
___Al + ___HCl --> ___AlCl3 + ___H2
2Al + 6HCl --> 2AlCl3 +3H2
What's the difference between a compound and a molecule?
Compound = 2 or more atoms of DIFFERENT elements chemically bonded together
Molecule = 2 or more atoms chemically bonded together
What type of bonding is present when atoms gain or lose electrons?
ionic bonding
In metallic bonding, how are the atoms / positive ions arranged?
layer upon layer
regular pattern
0.5076 - 0.508
Compare the J.J Thompson's plum pudding and Niels Bohr's models of the atom.
J.J Thompson:
No nucleus
No protons
No electron shells
How can a soluble solid be separated from a liquid?
Evaporation OR Crystallisation OR Distillation
Name the type of bonding and structure of NH3
covalent bonding
simple molecules
Explain why NaCl cannot conduct electricity as a solid but can conduct electricity when dissolved in water.
Solid = ions are not free to move
Dissolved in water = ions are free to move
How many atoms are there in 100g of Fe?
Avogadro's constant is 6.022 x 1023
1.075 x 1024 atoms
Balance the following equation:
___BF3 + ___ Li2SO3 --> ___B2(SO3)3 + ___LiF
2BF3 + 3Li2SO3 --> B2(SO3)3 + 6LiF
What is the method I could use to separate different colours of ink in a pen?
Chromatography
Explain the differences in properties between a pure metal and its alloy
Different sized atoms
Layers are disrupted
Layers cannot slide easily
In terms of the structures, explain why diamond cannot conduct electricity but graphite can.
Each C in diamond has 4 C-C strong covalent bonds.
Each C in graphite has 3 C-C strong covalent bonds. Each C has a delocalised electron which carries the charge through the structure
Zinc oxide is heated with carbon to make zinc and carbon monoxide. How much zinc oxide do you need to make 65g of zinc?
ZnO + C → Zn + CO
81g
Calculate the relative atomic mass of copper. Give your answer to 3 s.f.
Copper-63 has percentage abundance of 69.2
Copper-65 has percentage abundance of 30.8
63.6
Explain the steps of separating a soluble salt and sand.
In the end, you must have solid salt and sand separately.
1. Add water, stir until the salt is dissolved.
2. Filtration, filtrate = salt water, residue = sand
3. Evaporation / Distillation, salt crystals
Suggest 1 reason why silver nanoparticles are more effective than bulk silver at killing bacteria
larger surface area
large surface area : volume ratio
Draw a dot and cross diagram for MgCl2 on the whiteboard.
I decide!
How many ions are there in 100g of NaCl?
Avogadro's constant = 6.022 x 1024
Mr NaCl = 23 + 35.5 = 58.5
moles = 100/ 58.5 = 1.709401709 mols
Particles = mols x 6.022 x 1023 = 1.029401709 x 1024
x2 (there are 2 ions) = 2.0588 x 1024 ions
State and explain the reactivity trend shown in Group 1 metals
Reactivity increases down the group.
There are more electron shells as you go down the group.
Electron in the outer shell further away from the nucleus.
Less attraction to the positive nucleus
The electron is easily lost.
Explain how to calculate the Rf value from a chromatogram
distance spot travelled
divided by
distance solvent travelled
(number is always less than 0 )
Draw a dot and cross diagram for N2
I decide!
Describe Buckminster Fullerene.
C60
Allotrope of carbon
Spherical molecule - can insert small molecules inside
A student adds 9.6g of magnesium to excess dilute hydrochloric acid. What mass of HCl would be needed?
___ Mg + ___ HCl → ___MgCl2 + ___H2
28.8g