Synoptic Prep

Question 1

Give two features of a reaction in dynamic equilibrium.

Answer 1

-forward and reverse reactions proceed at equal rates
-concentrations (of reactants and products) remain constant
or
concentrations (of reactants and products) stay the same

Question 2

State what can be deduced about the chemical equation for this equilibrium.

Answer 2

More moles on RHS than left

Question 3

Define relative atomic mass

Answer 3

mass of one mole of atoms/
1/12th mass of one mole of a ^12C atom

Question 4

State how the relative abundance of 185Re+ is determined in a TOF mass spectrometer.

Answer 4

At the detector the ions gain an electron.
Relative abundance depends on the size of the current

Question 5

Ionic equation for reaction between potassium manganate(VII) and acidified hydrogen peroxide.

Answer 5

5H2O2+ 2MnO4^-+ 6H^+—>
2Mn^2+ +8H2O +5O2

Question 6

State why an indicator is not added in this titration

Answer 6

Because the solution goes from clear to pink at end point

Question 7

whats the reaction when aluminium oxide reacts with sulfuric acid.

Answer 7

Al2O3 + 3H2SO4–> Al2(SO4)3 + 3H2O

Question 8

Identify a reagent or test that could be used to distinguish between SO2 and SO3 and state observations

Answer 8

-universal indictaor
so2: orange/red
-so3: orange

Question 9

equation for the reaction of phosphorus(V) oxide with sodium hydroxide
solution.

Answer 9

P4O10 + 12NaOH –> 4Na3PO4 + 6H2O

Question 10

Draw the displayed formula of the molecule formed when phosphorus(V) oxide reacts
with water.

Answer 10

-double bond o to phosphorus
-3 o-h attached to phosphorus by o

Question 11

Explain why the melting points of these substances are different.

Answer 11

-NaCl has a giant ionic lattice ionically bonded by attractions between positive and negative ions
-cl2 and hcl both have a simple molecular structure with van der waals and pdds
-cl2 is bigger than hcl therefore has stronger imf and higher mp
-nacl has ionic bonds and ionic bonds are stronger than imf thus the highest mp.

Question 12

An experiment was done to measure the time, t, taken for a solution of iodine to react
completely when added to an excess of an acidified solution of butanone.
Suggest an observation used to judge when all the iodine had reacted

Answer 12

brown to colourless

Question 13

Describe and explain the shape of the graph in Figure 1.

Answer 13

As T increases rate (1/t ) increases OR time for completion decreases
Exponentially
OR
By a greater/ increasing factor
Many more particles have E ≥ Ea

Question 14

Suggest the type of polymerisation

Answer 14

Addition polymerisation

Question 15

State and explain the effect of using a higher temperature on the equilibrium yield of
tetrafluoroethene

Answer 15

Yield would increase
Equilibrium opposes temperature increase
Moves in the endothermic direction

Question 16

Explain why the strength of the interaction between two cysteine R groups differs from
the strength of the interaction between a serine R group and an aspartic acid R group.

Answer 16

Two Cys R groups form a disulfide bridge/link stated or described
Ser and Asp R groups form Hydrogen bonds
Disulfide bridges are stronger than Hydrogen bonds
Because disulfide bridges are covalent bonds (while Hydrogen bonds
aren’t)

Question 17

Deduce the type of interaction that occurs between a lysine R group and an
aspartic acid R group

Answer 17

ionic

Question 18

define mean bond enthalpy

Answer 18

the standard enthalpy change when one mole of gaseous molecules each break a covalent bond to form two free radicals averaged over a range of different compounds

Question 19

Suggest, with a reason, one other appropriate safety precaution for this experiment.

Answer 19

Wear gloves
Conc phosphoric acid is corrosive

Question 20

Suggest, with a reason, one other appropriate safety precaution for this experiment.

Answer 20

to remove (excess) acid