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Chemistry: Post your doubts here!
If I did not remember the wrong idea they should all be colourless. Sometimes hydrogen bromide and iodide can show yellow colour due to minor oxidation. -
Chemistry: Post your doubts here!
You're right. That was truly a silly mistake. :P -
A2 Physics | Post your doubts here
Okay I get it. Thanks. Physics P4 is over but I still need to get clear some points. It's not just for the exams, right? :P -
Mathematics: Post your doubts here!
The 94% probability is the area in the MIDDLE, which means there is a "tail" on either side, of 3% probability. When you look for z value you need to count from the left side, or negative infinity. So here the probability is 0.94 + 0.03 = 0.97 -
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A2 Physics | Post your doubts here
Guys I have a doubt in the telecommunication chapter. When concerned with signal attenuation and noise calculations always involve the unit decibel (dB), and there is one question asking why use the decibel as unit. I have no idea at all with this question. :P Can anyone explain to me the point... -
Further Mathematics: Post your doubts here!
I'm sorry but what do you mean by accelerated maths? I began to take further maths after I finished a-level pure & applied maths. -
Chemistry: Post your doubts here!
Virtually the reaction does NOT limit the amount of the reactants involved. What if two moles of E reacts with one mole of C? The product should be diester then. On the other hand, the MS has stated "allow either monoester" so drawing only one ester in the product is also correct. -
Chemistry: Post your doubts here!
From (b) there is 0.04 mole of ethanoic acid remaining in the equilibrium mixture. Originally there is 0.1 mole of ethanoic acid, so 0.06 mole of it has reacted to form R ethanoate. According to the equation 1 mole of ethanoic acid reacts with 1 mole of R hydroxide to form 1 mole of R... -
Chemistry: Post your doubts here!
a) is PbO2 + 4H(+) + SO(2-) + 4e(-) ------> PbSO4 + 2H2O b) I guess it is PbSO4 + 2e(-) ------> Pb + SO4(2-) [water here just provides aqueous environment] Then for (c) PbO2 + 4H(+) + 4e(-) ------> Pb + 2H2O -
Chemistry: Post your doubts here!
This can be possible. The question only asks for ionic equation so you don't have to worry about where the ions come from. Perhaps the some or all of the hydrogen ions are provided by another kind of acid like HCl. :P Here the sulphuric acid has two functions, one as an reactant for the... -
Chemistry: Post your doubts here!
This one is impossible. Lead is not reduced at all in this reaction. -
Further Mathematics: Post your doubts here!
Looks like my presumptions are non sense. :P Anyway I'm glad that my reply did help you. :D -
Further Mathematics: Post your doubts here!
That's okay. And this question... I presume that you did not read it carefully enough :P Here's the working -
Further Mathematics: Post your doubts here!
It's very simple if you use conservation of energy. -
Further Mathematics: Post your doubts here!
The first part The second part The third part F1 = mg cos θ - f It is sure that F1 ≤ mg and that cos θ ≤ 1 Deduced that f ≥ 0 So R ≥ 0. There must be contact. -
Chemistry: Post your doubts here!
I think the volume change is negligible. -
Mathematics: Post your doubts here!
2 xx - 12 x +13 = 2 (xx - 6 x) + 13 = 2 (xx - 6 x + 9 - 9) + 13 = 2 (xx - 6 x + 9) -18 + 13 = 2 (x - 3)^2 - 5 a = 2, b = -3, c = -5 -
Further Mathematics: Post your doubts here!
The tension can be zero since at this point weight provides the entire centripetal force. As long as the circular motion is maintained, it is okay. -
Chemistry: Post your doubts here!
Mercury level rises in the right-hand limb, this means that the pressure in R increases. In 1, according to Le Chartelier's Principle, a rise in temperature would favour the forward reaction, thus the equilibrium position shifts closer to the products. In the reaction, every 1 mole of reactants...