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Discussion in 'International A And AS Level' started by XPFMember, Sep 29, 2011.
i need a help in this question why is it A?
When ever two stages are involved in reaction its ethalpy profile diagram will have two humps in its graph .......as it is stated in the question X-Y is positive thus it will be endo and reactants will have low energy than the products....in Y-Z ethalpy change is neg thus its exo and reactants will have high energy than products as shown in option A
So it can't be B r8
No....no humps in the graph
K thx soo much
https://www.xtremepapers.com/community/threads/as-level-chemistry-mcq-help.47789/ HELP HERE
The balanced equation should be 10Al + 3Ba(NO3)2 = 5Al2O3 + 3BaO + 3N2 , right? therefore we will get a different answer..
plz reply as soon as possible..
Can anyone help me please?
What is involved in the mechanism of the mechanism of the reaction between aqueous sodium hydroxide and 2-bromo-2-methylbutane?
A heterolytic bond fission, attack by an electrophile on a carbanion
B heterolytic bond fission, attack by an nucleophile on a carbocation
C homolytic bond fission, attack by an electrophile on a carbanion
D homolytic bond fission, attack by an nucleophile on a carbocation
2-bromo-2-methylbutane is a tertiary halogenoalkane and will undergo sN1 'unimolecular' via carbocation reactions.
The C-Br bond will be broken heterolytically and a carbocation ion will be formed. The carbocation would then be attacked by the nucleophile (OH-)
I don't have the context of the full question.
But in both equations, the ratio of Ba(NO3)2 and N2 happens to be 1:1. Therefore, it's a coincidence that the answers ended up to be the same.
Can you answer my question please?
are you talking about this question
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lime stone is CaCO3
lime is CaO or Ca(OH)2
now all three would react with acids because acids react with carbonates (CaCO3) and bases (CaO/Ca(OH)2)
But old lime mortar effervesces (which means produces a gas), so this would be CaCO3 as it would produce CO2 gas with HCl
between A and D, D would be correct as water is present as well so quiklime would be Ca(OH)2
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