Random Shit Flashcards
What differences in physical properties can isotopes have?
Higher mass isotopes =
• higher m.p. + b.p.
• higher density
What’s the mass of an electron?
1/1836
Define conjugate acid-base pair
2 species differing by H+
Assumptions made for weak acids
• [H+] = [A-]
- Breakdown of H2O = neg
- for every [HA] breakdown -> 1 [H+] + 1 [A-]
- except v.weak acids/v.dilute ∵ H20 breakdown = sig
• [HA]equi = [HA]start
- ∵ [HA]start»[H+]equi
- so little [HA] breakdown ∴ = neg
- except ka> x 10-2/v.dilute
Methyl orange range
3-4 pH
Phenolphthalein
8-10 pH
Standard electrode potential
E.m.f. of a half cell compared to a H half cell
State the standard conditions
How does ligand substitution allow haemoglobin to transport O2 in blood
O2 bonds to Fe2+
When required O2 is substituted
How can an aq solution of an acid contain -OH
Water dissociates
H2O -> H+ + -OH
Give 2 reasons why it is uncertain whether reactions predicted from E values may acc take place
Conditions not standard
High Ea/slow rate
Suggest why methanol is added to petrol
It adds O2
Deduce feasibility of a reaction based on electrode potential
If overall cell potential > +0.40V = likely
>0.00 = feasible
< 0.00 = not feasible
Explain in terms of equi why cell potential increase E.g. Cu2+ + 2e -> Cu
If water is added
- H2O reacts w/ Cu2+ ∴ [Cu2+] decreases + equi shifts to left
- more e released by Cu
- cell has bigger difference in E/more negative
Explain in terms of electrode potentials why Cr is more reactive than Cu
- E for Cr is more negative
* Cr shifts left and Cu shifts right
In presence of CO, less O2 is transported in the blood. Suggest why in terms of stability constants
W/ CO stability constant > than O2
∴ bond w/ CO is stronger
Describe action if platin in treatment of cancer patients
Stops cancer cells from replicating
What important factors should you consider when deciding the most suitable indicator
- vertical section match pH range
- colour change
- end point
2 advantages of using fuel cells compared w/fossil fuels
- greater efficiency
* less greenhouse gases/only H2O formed
1 adv of using methanol than H in a fuel cell
- liquid ∴ easier to store/transport
* give a greater cell potential
Describe bonding in water
H bonds between H + lone pair
Describe the relative energies of 2s orbitals and each of the three 2p orbitals in a nitrogen atom
P orbital E > s orbital
P orbitals are equal in E
Why do some people consider use of H uses more energy than fossil fuels
E required to produce H
Difference between fuel cell + conventional electrochemical cell
Fuel cell converts E from reaction of fuel + O2
Salt
When H atom/s in an acid is replaced w/a metal ion/+ve ion
