Section 1 Flashcards
What do compounds with ionic bonding always have?
Giant ionic structures.
How are giant ionic structures held together?
Closely packed 3D lattice arrangement by the attraction between oppositely charged ions.
What is the electrostatic attraction between oppositely charged ions?
Very strong.
Why is the boiling point of giant ionic structures so high?
A lot of energy is required to overcome the strong attraction.
How do the charges of the ion affect the structure?
It affects the strength of the ionic bonding. 2+ or 2- is stronger than 1+ or 1-.
What do higher charged ions mean?
Higher melting and boiling points.
In diamond what does each carbon atom form?
Four covalent bonds in a very rigid giant covalent structure.
What is the hardest natural substance?
Diamond.
What is diamond used for?
Drill tips and cutting tools.
In graphite what does each carbon atom form?
Three covalent bonds creating layers.
What do the layers in graphite allow?
Free to slide over one another.
What does this mean graphite is good for?
A good lubricant.
What does the sliding also do?
Leaves free electrons, so graphite is the only non-metal which is a good conductor of electricity.
How can the theoretical yield be calculated?
From the balanced equation.
Percentage yield =
actual yield / theoretical yield x 100
What does 100% yield mean?
You got all the product you expected to get.
What is 6.023 x 10 to the 23?
Avogadro’s number or the Avogadro constant.
What can you think of a mole as?
The Avogadro number of particles in a substance, where the particles are atoms, molecules, ions or electrons.
One does one mole of any gas occupy at room temperature and pressure?
24 dm3.
Volume =
moles of a gas x 24
Volume =
mass of a gas / Mr of gas x 24
In electrolysis what will be produced at the cathode in an aqueous solution with sodium?
Hydrogen.
In electrolysis what will be produced at the cathode in an aqueous solution with copper?
Copper.
In electrolysis what will be produced at the anode if a halide is present?
The halide.
In electrolysis what will be produced at the anode if no halide is present?
Oxygen.
What ions are in sulphuric acid solution?
SO42-, H+, OH-.
What is formed at the cathode in sulphuric acid?
Hydrogen.
What is the half equation for the production of hydrogen?
2H+ + 2e- -> H2
In sulphuric acid what is formed at the anode?
Oxygen and water.
What is the half equation for the production of oxygen and water?
4OH- -> O2 + 2H20 + 4e-
What ions are in sodium chloride solution?
Na+, Cl-, OH- and H+.
What is formed at the cathode in sodium chloride?
Hydrogen.
What is formed at the anode in sodium chloride?
Chlorine gas.
What is the half equation for the production of chlorine gas.
2Cl- -> Cl2 + 2e-
What ions are in copper (II) sulphate solution?
Cu2+, SO42-, H+ and OH-
What is produced at the cathode in copper sulphate?
Copper metal.
What is produced at the anode in copper sulphate?
Oxygen and water.
What is the half equation for the production of copper metal?
Cu2+ + 2e- -> Cu.
What does the amount of product made by electrolysis depend on?
The number of electrons that are transferred.
What happens if you increase the number of electrons?
You increase the mount of substance produced.
How can you increase the number of electrons?
Electrolysing for a longer time, increasing current.
What does one amp flowing for one second mean?
A charge of one coulomb has moved.
Q =
It.
What does 1 faraday contain?
One mole of electrons.
When working out the mass of something in electrolysis what are the steps?
- Write balanced half equation for cathode.
- Calculate number of faradays (amps x time (s)) .
- Calculate number of moles of substance produced (faradays divided by number of electrons in half equation).
- Work out mass = Mr x moles.
