wrong questions
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explain why halide ions are present in the mixture containing a halogenoalkane which only has covalent bonds
-halogenoalkanes hydrolyzed by water -c-halogen bond breaks
define term structural isomerism
-same molecular formula -but different structural arrangement
Give three reasons why the product may be removed before its maximum concentration is achieved.
-eqm pos shift to the right -remove prod to avoid formation of reactants -time to reach eqm too long -unreacted reactants recycled
nickel catalyst is used in the first stage Explain why the catalyst is more effective when coated onto an unreactive honeycomb. (2)
inc suface area more successful collisions
The pool manager maintains the water at a pH slightly greater than 7.0 Explain how this affects the equilibrium established when chlorine is added to water. (2)
Hydroxide / alkali ions react with the acids Equilibrium moves to the right
Explain why chlorine is used to kill bacteria in swimming pools, even though chlorine is toxic
Only used in small amounts The health benefits outweigh the risks
Describe in outline a method to show that the manganese(IV) oxide is not used up in the decomposition of hydrogen peroxide and that it still functions as a catalyst. (heterogeneous catalyst) 4
filter solid from solution after experiment dry reweigh solid repeat after experiment to see if identical results
The third reaction in the airbag is between the metal oxides and silicon dioxide. State the type of reaction taking place and justify why this reaction is necessary. 3
neutralisation sodium is corrosive salt is inert
Give a reason why the measurement of the initial rate of reaction is likely to be less accurate than the measurement of the maximum rate.
hard to draw an accurate tangent
react why Naco3 added to organic layer and why it is important to open tap after adding this solution
react w excess hcl release co2
greenhouse gases can absorb infrared radiation. co2 absorbs and o2 does not 2
co2 has polar bonds o2 does not have polar bonds polarity of co2 changes/dipole moment shifts
one disadvantage of cl higher than 3 and lower than 1 cl2 + h2o - hcl + hclo 4
lower- hclo lower ineffective bleach higher- hcl higher skin irritation eye irritation
shows the steps reaction of barium carbonate in limewater test
-baco3 + 2hcl - bacl2 + co2 + h20 -ca(oh)2 + co2 - caco3 + h20
student suggests diff in rate of reaction of strontium and barium with water due to diff of sum of first and second ie discuss suggesting 6
-sum of first 2 ie for barium is lower -ba bigger atom - ba more shielding -outwiegh other factors -ba greater nuclear charge -ba reacts faster
explain in terms of redox reaction occurring why said halides form different products with concentrated sulfuric acid
-iodide ions better reducing agents -because iodide ions lose e more readily
the melting temp of nas2 is higher than nacl2 even though both is ionic bonding explain diff in melting temp 2
attractive forces between sodium ion and anion is greater with sulfide - sulfide ion has a higher charge than the chloride ion
describe key feature of bonding of carbon atom in graphite that results in it being an electrical conductor 2
one e free to move each carbon bonded to 3 others
suggest why the addition of anhydrous calcium chloride to water results in an increase in temp and a decrease in volume
hydration of ions is exo shorter bonds between ions and water mol
what is meant by term salt
h^+ in an acid is replaced by a metal ion
give a reason why only the proton from carb acid group and not from methyl group is donated 1
loss of h from oh by delocalization of charge of or stabilization on carboxylate ion
why is ka of glycolic acid is 10x larger than ethanoic (glycolic 2 oh) 2
.extra oh the o withdraws e .stabiles anion/ weaken oh bond/ h+ lost more easily