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  1. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    (b) Just draw the basic alcohol structure of C4H9OH. Saturated - Because it has carbon-carbon single bonds. (d)(i) Acid (Ethanoic Acid) first then Alcohol (Ethanol). The formula is CH3COOC2H5.
  2. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    NaCl (s) ---> NaCl (aq.), Enthalpy change = +ve.
  3. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    (ii) Mass increase at cathode = 1.44 - 1.20 = 0.24 g Mass decrease at anode = 1.45 - 0.24 = 1.21 g (iii) The current supplied by 80 A for 90 s = current supplied by 40 A for 180 s. So decrease in mass at cathode = 0.24 g Mass of cathode = 1.51 + 0.24 = 1.75 g
  4. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    It's not part of our syllabus, this is calculated using bond energies, the energy involved in bond breaking is less than the energy involved in bond making.
  5. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    It's exothermic.
  6. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    20 deg. C is room temperature. If melting point and boiling point is below this then it is a gas, If boiling point is above and melting point is below this then it is a liquid, If both melting and boiling point are above this, it is a solid.
  7. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    It's pretty easy, Photosynthesis, Dissolving, Thermal Decomposition - Endothermic. Neutralization, Combustion - Exothermic.
  8. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Ions conduct electricity in Ionic bonds. Covalent compounds are not good conductors of heat and electricity because they have no free electrons.
  9. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    You should know the basics, such as photosynthesis, dissolving, neutralization, combustion, thermal decomposition.
  10. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Yeah.
  11. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    It depends. If the ionic bond is NaCl, then each Na ion is attached to 4 Cl ions and the converse is also true. In MgCl2, each Mg ion is attached to 6 Cl ions. And so on, But we don't have to study structures of the complex lattices.
  12. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Look at it like this, Ratio from equation, 1 : 2, From calculations, 1 : 2 = 0.05 : 0.075 Now, from this, we can tell that, 0.05 moles of Zn requires 0.1 moles of HCl but only 0.075 is present. So HCl is limiting agent or you can say, Zinc is in excess.
  13. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Which one? :confused:
  14. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Remember these, Oxidation is gain of oxygen, loss of hydrogen and loss of electrons. Reduction is loss of oxygen, gain of hydrogen and gain of electrons.
  15. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    The large gravel is to separate twigs and large substances. The small sized gravel is to separate mud, sand and smaller substances. The carbon is used to remove tastes and odor from the water. The chlorine is used to kill bacteria.
  16. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Find the moles ratio using the equation. Calculate the number of moles of each reactant by the given mass/volume. The reactant that has the greater quantities of moles than required for the reaction (by mole:mole ratio) is in excess. The other one is the limiting agent.
  17. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    I googled the second part, it is true. The metal oxide undergoes synthesis reaction with carbon dioxide to form metal carbonate.
  18. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Yes they do, when the more reactive metal oxides from Potassium Oxide to Aluminium Oxide react with water they form Metal Hydroxides. However, this depends on their reactivity and solubility, aluminium oxide is sparingly soluble and less reactive so the reaction is rather slow. For carbonates, I...
  19. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    Acids are confirmed by the following properties: - pH (lower than 7). - Reactions with Metals, Metal Oxides/Hydroxides, Metal Carbonates. So, the answer is D. Oxidizing Agents: -Acidified Potassium Dichromate (VI), KCr2O7, it OXIDIZES other compounds and itself is REDUCED, the oxidation state...
  20. Saad Mughal

    Biology; Chemistry; Physics: Post your doubts here!

    The catalyst simply helps to reach equilibrium quickly, since time is money in industry, it is helpful.
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