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AS chemistry Unit 2.. Ready?

R

rose rose

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pls help,
1.using bacteria to bring about chemical coversion such as the production of latice acid from plant chemicals can bring green chemistry .there can be disadvantages suggest:
A.one advantage
B.one disadvantage
pls answer pls......
 
Y

yousef0074

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an advantage could be that bacteria is used instead of fossil fuels which are non- renewable resources, and when burned the produce CO2 and unburnt hydrocarbons.

a disadvantage could be that energy is needed to grow the plants which requires fuels to be burned, and to make fertilizers. Also, the need of separation of products such as distillation which is an energy demanding process
 
R

rose rose

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yousef0074 said:
an advantage could be that bacteria is used instead of fossil fuels which are non- renewable resources, and when burned the produce CO2 and unburnt hydrocarbons.

a disadvantage could be that energy is needed to grow the plants which requires fuels to be burned, and to make fertilizers. Also, the need of separation of products such as distillation which is an energy demanding process
Click to expand...

Thanx:)
 
D

.DR.me.

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U stalking ME said:
solubility of sulfates (opposite for solubility of hydroxides)
the lattice energy is always negative as it is always favoured for negative gaseous ions to come together to form a solid - opposite charges attract. so, the numerical values of lattice energy would decrease as you go down a group because size of ion gets bigger, interaction of ions get weaker, so less favoured, but it increases across a period because size gets smaller and charges increase.However down a group, the bigger the size, the lesser is the interaction with the water molecule(the hydration), so the enthalpy of hydration becomes less favourable, hence less exothermic.so in overall, solubility decreases because size gets bigger down the group, lattice energy becomes less negative(more positive) and the enthalpy of hydration becomes more positive as well(because it is less favourable now for interaction with water molecule), hence if the overall enthalpy change(ie the sum of these two) is greater than zero, means you have to put in energy to dissolve them, therefore it becomes more insoluble down the group. In chemistry, exothermic reactions are more favourable, endothermic reactions are less favourable. in a sense, the enthalpy becomes more endothermic, or less exothermic down a group for dissolving so solubilities decrease.
Click to expand...
but thats regarding hydroxide only ?
 
D

.DR.me.

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I need something >
need questions for each chapter with answers , as i was solving from the pastpapers and realised i cant relate
Help :/ , i studied well , but keep on forgeting , not sure whats missing -_-
 
D

.DR.me.

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another question >
which of the following could not be an element in group 2
as to the mark scheme the answer was > an element with a chloride which is liquid at room temp ? well seriously ? :sick: i just studied the rxn > MO +2HCL ---> MCL2 (((aq))) + H2O ?
i thought an element with an oxide that forms a solution with a PH of 10 is the one to be correct , since metal oxide supposed to be acidic since it attracts base ?? correct me if am wroong !
 
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