• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Search results

  1. E

    Chemistry: Post your doubts here!

    Few things to note: All structural isomers have the same molecular weight of 266.5 Only the chloride ions not bonded to to Cr react (the ones outside the brackets) n(AgCl) = n(chloride ions) So, the number of moles of chloride ions outside the brackets is the same as the number of moles of AgCl...
  2. E

    Mathematics: Post your doubts here!

    Graph of the two lines, perpendicular distance d and theta the angle of the tangent with the x-axis. Form the line equation: tan(theta) = gradient of tangent tan(theta) = 0.5 You can get sin from tan by: 1. Drawing a triangle where tan(theta) = 0.5, opp side = 1 and adj side = 2 2. Use...
  3. E

    Chemistry: Post your doubts here!

    Atomic weight from periodic table.
  4. E

    Chemistry: Post your doubts here!

    Atomic mass is the weighted average of isotopic masses: 10.8 = 19.78%(10.0129) + 80.22%(m) m = 10.9941 (6sf)
  5. E

    Chemistry: Post your doubts here!

    may june 2016 42 Can someone explain why in the ms they take the concentration of ch3nh2 as y instead of y - 3.966 x10^-4 ?
  6. E

    Mathematics: Post your doubts here!

    What do you mean it didn't reach the bottom? it did bounce off the bottom of the tank. The one in the question as dropped from a height above the surface of the water and it didn't exceed that height.
  7. E

    Mathematics: Post your doubts here!

    Why would it not be possible? as long as the ball's maximum height isn't higher than the height it was dropped off from.
  8. E

    Chemistry: Post your doubts here!

    You're looking for a jump in successive ionization energies, which means that all the outermost electrons were removed and the next one is in an inner shell. B has a jump between two and three, which means that it has two valence electrons, group 2. C has a jump between one and two, one...
  9. E

    Chemistry: Post your doubts here!

    From part b we we know that: 0.04 mol of NaOH reacted with ethanoic acid mol ratio of NaOH to ethanoic acid in the reaction is 1:1 therefore, there was 0.04 mol of ethanoic acid in the equilibrium state before the equilibrium state there was 0.1 mol of ethanoic acid so the other 0.06 mol of...
  10. E

    Physics: Post your doubts here!

    The frequencies in the graph are F-f, F, F+f where F is the freq of carrier wave and f is the freq of the signal wave (i) F = 909kHz lambda = 330 m (ii) and (iii) Bandwidth is the range of frequencies used for transmission In general, bandwidth = (F+f) - (F-f) = 2f Bandwidth = 918 - 900 = 18...
  11. E

    Physics: Post your doubts here!

    (i) ratio of input to output = (64)(0.21) dB ratio of output to noise = 25 dB ratio of input to noise = 25 + 13.44 = 26.88 dB Normally you would multiply ratios to combine them, but since the decibel is in a logarithmic scale you add the ratios. (ii) 26.88 = 10 log(P/9.2μ) P = 4.5x10^-3
  12. E

    Mathematics: Post your doubts here!

    A) Prob = combinations with tracey and albert/all combinations Two possible groups according to the rules: 5M1W and 4M2W all combinations = (10C5)(9C1) + (10C4)(9C2) = 9828 5M1W One women and one man are chosen, that leaves 4 men to be chosen from 9 men. That gives us 9C4 combinations 4M2W...
  13. E

    Mathematics: Post your doubts here!

    Don't think so, but it shouldn't take that much time if you're starting from the greatest value of x till you reach P(X≥x) >0.1.
  14. E

    Mathematics: Post your doubts here!

    (i) p(x) = (x**2 - x + 1)(ax**2 + bx + c) (Other factor must be a quadratic to get x**4 in p(x)) The roots of the factors will also be roots for p(x) You get two complex roots using the quadratic equation on x**2 - x + 1 Substitute one root and solve p(root) = 0 (ii) Get ax**2 + bx + c by...
  15. E

    Mathematics: Post your doubts here!

    The image isn't loading for me.
  16. E

    Mathematics: Post your doubts here!

    Not sure what you mean by men not being mentioned. But it's a similar idea. M H M notH F H F notH p(F or H or F H) = 1 - p(M notH) Since M notH is the only group that won't be counted in (F or H or F H). = 1 -(3/4)(2/5)
  17. E

    Mathematics: Post your doubts here!

    Please copy paste the actual question next time. Q:In a group of 30 teenagers, 13 of the 18 males watch ‘Kops are Kids’ on television and 3 of the 12 females watch ‘Kops are Kids’. (i) Find the probability that a person chosen at random from the group is either female or watches ‘Kops are Kids’...
  18. E

    Mathematics: Post your doubts here!

    (a) Number of terms in the brackets = {1,2,3,...} Number of terms in the first n brackets = sum of terms up to the nth bracket = sum of numbers from 1 up to n So you use [n(n+1)]/2 to get that sum (b) Only the terms = {1,4,7,10,...} It's a arithmetic progression with this formula: t = 1+...
  19. E

    Physics: Post your doubts here!

    A2 op-amp question. This is from the cie application booklet: Can somebody explain how D2 blocks the back emf from affecting the op-amp exactly? Thanks.
  20. E

    Chemistry: Post your doubts here!

    Yes. Molecular mass: sum of atomic masses of atoms in a molecule Atomic mass: weighted average of isotopic masses Isotopic mass: mass of isotope (All relative to 1/12th of C-12) The sample is going to have different stable carbon isotopes with different masses. The atomic mass derived from the...
Top