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Chemistry: Post your doubts here!
Out of every 100 g of fertilizer, 30 g is P205. Out of 30 g of P2O5 , mass of P = (2 x Mr of P/Mr of P2O5) x 30 g = (62/142) x 30 g =13.1 g -
Seeking Feedback from Chemistry Students both O and A levels
Hi all, A question popped into my mind as I was answering some queries on the chemistry thread. Past year papers with their marking schemes could be easily downloaded from this forum, what is not included are explanations to the MCQ answers. My question is- are there any books sold in your... -
Chemistry: Post your doubts here!
hmm...Try creating 3 balanced equation for their combustion. If you are still stuck, then I'll provide the answers. -
Chemistry: Post your doubts here!
Q10. Taking X as monobasic acid and Y as monoacidic base... If X was strong acid, [H+] = 2M , pH = -log(2) = -0.3 . So student P is wrong. For student Q, I'll use reasoning rather that complicated maths formula. Imagine adding both X and Y into seperate glasses of neutral water (pH=7). Note... -
Chemistry: Post your doubts here!
You can check out page 462. #9228 and #9239 -
Chemistry: Post your doubts here!
Q16. Check that the oxidation state of silver before and after the reaction is +1, it means that it is neither oxidized or reduced. This effectively eliminates options B, C and D. silver chloride is insoluble and the silver complex formed is soluble. Q28. Since this is a paper from long ago, I... -
Chemistry: Post your doubts here!
I'll discuss this as a theoretical thought procedure, rather than an attempt to predict what experiment is expected. Some of the procedure are straightforward in theory, but not easy to carry out accurately with limited lab apparatus. The amount of CaCO3 could be measured by 1) heating mixture... -
Chemistry: Post your doubts here!
I2 (solid) --> I2 (gas) The bond broken is from one I2 molecule to other I2 molecules, which is induced dipole (as I2 are non polar). Covalent bonds are NOT broken as the molecules are not broken into atoms. -
Chemistry: Post your doubts here!
hmm...to be fair, solubility is not a clear cut property. So sometimes in MCQ, its an issue of selecting the BEST possible option out of the 4. Mind sharing which paper give the idea to view ester as soluble? -
Chemistry: Post your doubts here!
w07qp1 Qn 9 : moles of SO3 2- : moles of electrons : moles of metal 0.0025 : ? : 0. 005 1 :? : 2 1 : 2 : 2 2 mol of metal gained 2 mol of electrons 1 mol of metal gained 1 mol of electron (oxidation state will thus decrease by 1) Original oxidation state of metal = +3 Final oxidation state =... -
Chemistry: Post your doubts here!
Ethyl ethanoate is not very soluble in water. -
Chemistry: Post your doubts here!
Notice that the Y-axis is measuring speed of reaction, not amount of products. When the reactants gets used up towards the end, the speed of reaction drops back towards zero. -
Chemistry: Post your doubts here!
Q1. Find out the number of moles of O2, since 1 mole of gas occupies 24000 cm^3 at RTP. moles of O2 = 500/24 000 molecules of O2 = moles x 6.02 x 10^23 = (500/24000) x 6.02 x 10^23 = 1.25 x 10^22 Q2. Comparing the original structure to the resulting structure, we see that 5 C=C double bonds... -
Chemistry: Post your doubts here!
The decomposition temperature of CaCO3 is above 800 plus degrees Celsius if I remember correctly. Time taken to reach that temperature? Well, it depends on how strongly its being heated? This procedure that you are carrying out, is it based on the actual test question or is actually a self... -
Chemistry: Post your doubts here!
Do you mean to ask why X is not a straight chain butene? If it was a straight chain butene, we would get butane when it reacts with H2. since the question stated that we get methylpropane upon hydrogenation, it means the C4H8 is branched at the start. -
Chemistry: Post your doubts here!
Do you have the answers from the marking scheme? -
Chemistry: Post your doubts here!
Calcium carbonate does decompose. There will be a loss in mass due to release in CO2. (Note that this is not an clue to the experiment, I have no idea what it is.) -
Chemistry: Post your doubts here!
Hi, for ease of discussion, can put up the suggested answers for your 3 selected questions? w11qp12 Q4. N2 + 3H2 --> 2NH3 Mass of H2 reacted = 12 000 - 96 000 = 24 000 g Moles of H2 reacted = 24 000 / 2 = 12 000 mol Moles of NH3 produced = (12 000/3 ) x 2 = 8 000 mol Mass of NH3 produced... -
Chemistry: Post your doubts here!
This is one way to visualise the answer to Q28, I think a diagram is easier than the chunk to text I typed in #9228