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Chemistry: Post your doubts here!
To W07 Q9, is the answer B? This is a redox reaction, with the sulphite oxidised to sulphate. Oxidation and reduction always come together. With sulphur oxidised, the "metal" must be reduced. You can see the change in oxidation number of sulphur is plus 2 (from +4 to +6). So if 1 mole of "metal"... -
Mathematics: Post your doubts here!
3^(x+2) = 9 (3^x) 9 (3^x) = 3^x + 9 8 (3^x) = 9 3^x = 9/8 =1.125 x = ... -
Physics: Post your doubts here!
Use change in gravitational potential times mass. At height R, distance to Earth's centre is 2R. phi = -GM/2R At height 2R, distance is 3R. phi = -GM/3R Change in phi = -GM/3R - (-GM/2R) = GM/6R ΔE(p.e) = Δphi × mass = GMm/6R -
Further Mathematics: Post your doubts here!
Could you please draw a diagram to illustrate the situation? I am confused by the description. -
Chemistry: Post your doubts here!
Hi guys Can anyone tell me something about complex ions? One past paper question asked me to draw the displayed shape of d-orbitals of metal cation in complex ions, and to explain the energy differences among the d-orbitals. I felt like my teacher did not mention this part. :P -
Chemistry: Post your doubts here!
The oxidation number goes from +1 (for Na) to +4 (for Si) step by step. You need to talk about the number of electrons in the outer shell of each element and thus their ions' bonding abilities to the chloride ions. -
Chemistry: Post your doubts here!
H2O in the reactants does not count as solute molecule. So the reaction actually increases the mole number of solute molecule. nRT is now bigger, so Π ought to increase. -
chemistry p1 question problem
I don't think so. I have never heard of ligands in AS year. It should be in the A2 syllabus. Ligands are the ions or molecules which can combine with metal ions or atoms to form a complex. For example, Co(H2O)6, the water molecules behave as ligands in this complex. So in the question, the... -
Physics - telecommunication
Hei guys Does anyone know how much will the Telecommunication chapter (A2) take in the final exam? There is a lot of content in this chapter but my teacher said that it is not very important. -
Chemistry: Post your doubts here!
The "orbitals of principal quantum number 2" refers to the electrons in the 2nd energy level. Beryllium has 2 electrons on the 2nd level which are lone electrons. That is 0 pairs & 2 unpaired. A is incorrect. Carbon has 4 electrons on its 2nd level. Two of them are paired. So it is 1 pair & 2... -
Chemistry: Post your doubts here!
Is it C? I think Cl-35 Cl-37 and Cl-37 Cl-35 shall show as the same peak. The mass spectrometre measures the mass-to-charge ratio of Cl2 molecules, not Cl atoms. -
Assalamualaikum, and hey guys! :)
Welcome! I'm also doing A level this year :D- DragonCub
- Post #9
- Forum: Welcome Lounge
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Physics: Post your doubts here!
You can assimilate this with linear motion ;) charge = current × time displacement = velocity × time You must be familiar with calculation involving acceleration, aren't you? It is quite similar for charge. Here the "initial current" 100 mA, "final" 20 mA, "current acceleration" is... -
Mathematics: Post your doubts here!
With the gradient and a point, you can find the equation of the tangent. Use differentiation to find the gradient: dy/dx = -4/[3 (3x-4)^2] at P, x =2, dy/dx = -4/[3 (3*2-4)^2] = -1/3 This is the gradient of the tangent at P. Equation can be obtained: (-1/3) (x - 2) = y - 2 , y = (-1/3) x + 8/3... -
Further Mathematics: Post your doubts here!
And then it becomes exploiting the the techniques for integration? :D -
Physics: Post your doubts here!
Via intuition you can deduce that the extension in S3 is also x. The springs are identical, so their constant of elasticity can all be seen as k. Force on S1 (call it F1) is kx, so is force on S2 (call it F2). The resultant force of F1 and F2 is to the left, since their vertical components... -
Chemistry: Post your doubts here!
For Q17, "a strong acid" means concentrated sulphuric acid (conc. H2SO4) can neutralise bases and/or form conjugate bases; "an oxidising agent" indicates that conc. H2SO4 can make another element's oxidation state rise during reaction. In the choices: A, ethanol reacts with conc. H2SO4 but the... -
Further Mathematics: Post your doubts here!
Ahh... Is this the integration formula for surface area? Seems I have used the formula for volume by mistake. :P Thanks a lot dude.