Vocabulary
Define reducing agent/reductant.
A chemical species that causes another species to undergo reduction. Itself, undergoes oxidation by donating one or more electron.
Write the fermentation process of bioethanol.
•C6H12O6(aq)→ 2CH3CH2OH(l)+2CO2 (g)
(yeast on top of the arrow)
What functions similarly to the salt bridge in galvanic cells used in fuel cells?
The electrolyte
Which food item that can be found in the school canteen is Ms Lee allergic to?
Shin Ramyun
What is biodiesel? How is it made?
Biodiesel is produced by transesterification. Triglyceride reacting with methanol x3 to produce biodiesel and glycerol x1
Write a thermochemical equation for the combustion of ethane gas.
2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(l)
ΔH: -3120 kJ/mol
State the shift in direction if there is an increase in temperature for exothermic and endothermic reactions.
Increase in temperature:
Exothermic reactions: Shift backwards
Endothermic reactions: Shift forward
What 2 instruments can Ms Lee play?
Piano and violin
What is an electrolyte in primary/fuel cells? List one function of it.
A solution or liquid or gel that contains ions. Used to balance ion charges of the cell.
Calculate the amount of energy released when 3.60kg of butane is burnt in an unlimited supply of oxygen.
n=m/M = 3600g/58 = 62.1mol
Energy= n x Heat of combustion = 62.1 x 2880 = 178848 = 1.79 x 105KJ
State 2 advantages and 2 disadvantages using fuel cells in a commercial car.
ADV: lower emissions of greenhouse gases/ more quiet/ greater efficiency than direct combustion / low maintenance and running costs
DISADV: storage and safety issues with highly reactive Hydrogrogen gas/ expensive to make porous electrodes/ Not as efficient
How many years has Ms Lee been teaching Yr 12 Chemistry in NWSC? (Including your year)
5 years
What is the difference between Kc and Qc?
•The equilibrium constant, K_c , and the reaction quotient, Q_c, can be used to describe the extent (yield) of a reaction.
•Q_c is the expression for the ratios of concentration not at equilibrium; at any point during the reaction.
N2 (g)+ 3H2 (g) ⇌ 2NH3 (g)
If the volume is halved, using LCP explain which direction will the system shift.
If volume is halved, pressure increases. According to LCP, the system will shift forward to the lower number of particles to partially oppose the increase in pressure.
Compare the energy efficiencies in an AA battery compared to the Hydrogen-Oygen fuel cell.
AA battery: 60-90% efficient
Fuel cells: 40-60% efficient but if use the waste heat energy to continue making electricity, increases to 80-90% efficient.
What is Ms Lee's favourite colour and list 2 pets she had in the past.
Lilac / Purple
Fish/ turtle / hamster
Define "SUSTAINABLE" and how does it link to the sustainable development Goal 2: Zero hunger?
Substances that can be produced at a rate greater or equal to the rate of consumption without comprising future generations
Goal 2:Zero hunger is to make sure there is access to nutritious food for all. This links to minimizing waste by using renewable materials, like plants - biofuel.
What volume of Hydrogen gas is produced under an acidic environment when a current of 15A for 1 hour is carried out under SLC?
Q = I x t = 15 x 60 x 60 = 54000 C
n(e-) = Q/F = 54000/96500 = 0.5596 mol
n(H2) = required/given =1/2 x 0.5596 = 0.2798 mol
V(H2) = n x Vm = 0.2798 x 24.8 = 6.9 L
In a science experiment, compare the definition of "repeatability" and "reproducibility".
Repeatability -the consistency of results when an experiment is conducted multiple times by the same person, using the same equipment, and under the same conditions.
Reproducibility- the ability to obtain the same results when an experiment is conducted by a different person, using different equipment, or under different conditions.
State 5 things Ms Lee carries in her pencil case, always!
1. white board markers
2. scissor
3. ruler
4. pen/pencil
5. bulldog clips