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Physics: Post your doubts here!
Could you tell me which year it is? -
Chemistry: Post your doubts here!
...and i guess that if you want that rotation to occur you will have to break the pi system, and that requires energy. I´m not sure about this, so if anyone knows the answer please do say it. -
Chemistry: Post your doubts here!
Well, dont know if im right so if im not please do correct me! Its because when you have double bonds like in ethene, the pi system (which has a pi lobe above and below the plane) doesn´t allow rotation because there is no space for it to rotate (since its occupied by the pi lobe) -
Chemistry: Post your doubts here!
* A restriction for the bonds to rotate, thus becoming less flexible. -
Chemistry: Post your doubts here!
You are supposed to know that around double bonds there is a restriction of the carbon bonds and that for single bonds there isn´t. -
Mathematics: Post your doubts here!
Yes please someone solve that complex number question, if possible giving explanations. Thanks! -
A* physics doubt
Can you get an A* at A level physics if you have a medium grade B at AS and you score full marks on both the A2 papers? -
Chemistry: Post your doubts here!
Q5 - A is correct. Iodine is I2, a molecule, hence it has covalents bonds between the atoms. It also has van der Waals forces of attraction between I2 molecules. Q33 - Anything from Period 1 to Period 2 cannot have an expansion of the octet. Nitrogen is in Period 2 and so cannot expand its... -
Chemistry: Post your doubts here!
Q33 - electrons on sulfur = 16 , electrons on hydrogen = 1 , negative ion (gained one electron) = 1. Thus, 16 + 1 + 1= 18 electrons. Sulfur is similar to oxygen in that its valence electrons are on the s and p orbitals. Sulfur has 4 electrons on the p orbital and 2 electrons on the s orbital. So... -
Chemistry: Post your doubts here!
Was wondering... Say for option A that intermediate is correct, would you get the the desired product? Yes, right? -
Chemistry: Post your doubts here!
Q23 - When bond length increases, bond strength decreases. The change from chloroethene to PVC is from double bond to single bond. Double bonds are short meaning it is a strong bond (if you think about it, they are strong because you have sigma and pi bonding, hence more orbital overlap and... -
Chemistry: Post your doubts here!
Q13 - A is wrong because there is no hydrogen directly bonded to a very electronegative atom ie. Oxygen, Nitrogen or Fluorine. B is wrong because there is only one molecule... dimeric would be like Al2Cl6 - two AlCl3 molecules bonding to each other, in this case via dative bonding. C is wrong... -
Chemistry: Post your doubts here!
Q35 - Strontium ions are a bit smaller than calcium ions due to the bigger nuclear charge, so I guess if you help yourself with the Data Booklet and search for ionic radius and stuff you can see they are about the same size and conclude 1 is correct. Q31 - STATEMENT 3 is correct, nuclear charge... -
Chemistry: Post your doubts here!
Oh... 2^3 is indeed 8... my goodness i even said 2 x 2 x 2 = 6 :S This is what you get for not knowing how to multiply properly... Q28 - I totally agree with your structure now! Before you missed the aldehyde turning into a carboxylic acid and the oxidation of the C at the double bond with the... -
Chemistry: Post your doubts here!
Ok! It´s something you have to know. Acidified KMnO4 is such a strong oxidising agent that it will oxidise and break the double bond to produce CO2 + H2O if the cleavage occurs at a primary carbon atom; an aldehyde if the cleavage occurs at a secondary carbon atom or a ketone if the cleavage... -
Chemistry: Post your doubts here!
Abbbbby... I have researched a bit for Q28, and this is what I found: http://en.wikipedia.org/wiki/File:Carvone_oxidation.png Which I don´t get, plus, that product has 8 carbons and the question said X has 9 carbons. If you do understand please explain to me. With regards to your answer, I... -
Chemistry: Post your doubts here!
Q20: B- 2^3 = 6. If you know about statistics this is a bit easier. There are 2 possibilites around each double bond, either cis or trans. You have 3 double bonds in which this cis-trans combination can occur, hence it is 2 x 2 x 2 aka 2^3 = 6 (2 combinations for first double bond, 2 for... -
Chemistry: Post your doubts here!
Well ethanedial is simply a di aldehyde. Acidified potassium dichromate is used as an oxidising agent so will oxidize the aldehyde parts into two carboxylics. -
Main formulas for A2 physics - Applications
Oh didnt know that! Do you have the application booklet for the 2014 syllabus?