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Two different atoms have four protons each and the same mass. However , one has a positive charge while the other is neutral. Describe what each atomic structure could be, listing the possible number and location of all subatomic particles.
chemist carries out a reaction that generates several side products. Which of the following can she eliminate from the reaction mixture by washing with an aqueous solution of sodium hydroxide?
100.0 mL of a 0.500 M solution of KBr is diluted to 500.0 mL. What is the new concentration of the solution?
5.Balance the equation below and use it to answer the questions that follow:
C2O42-(aq) + MnO4-(aq) + H+(aq) = CO2(g) + Mn2+(aq) + H2O(I)
(I) Which ionic species is an oxidizing agent and which is a reducing agent
(II) Twenty five 25 cm3 of a solution of sodium ethanediote of concentration 0.1 mol dm-3 were placed in a conical flask. A burrete was filled with patassium manganate (VII) solution of concentration 0.038 mol dm-3 . Determine the volume of the manganate (VII) solution that would be needed to give the endpoint in the titration.
(III) Assuming that the KMnO4 was prepared by dissolving 6.94 g of salt in 1 dm3 of solution. Calculate the % purity of KMnO4
How many mL of water must be added to 250mL of 0.578 M CaCl2 solution to give a 0.349 M solution?
4. Write two equations to depict the amphitropic nature of water.
(b) define the following: (I) pH and (II) pKa
(c).For a reaction between a weak acids and water as shown, prove that pH =pKa -log [acid/base].
HB(acid) + H2O = H3O+ + B-
(d) List the factors that affect the solubility of a substances.
(e) Calculate the solubility in grams per litre of silver sulphide if the Ksp of Ag2S is 6.3 x 10-50
4.1 Use electronic factors to explain why methyl carbanion is more stable than tertiary butyl
carbanion.
4.3 Reaction of 2-methyl-1,3-butadiene with bromine yields a mixture of products: 3,4-
dibromo-2-methyl-1-butene (3 %), 3,4-dibromo-3-methyl-1-butene (21 %) and 1,4-
dibromo-2-methyl-2-butene (76 %).
a) Identify all products as either 1,2 or 1,4 adducts.
b) Propose mechanisms for the formation of all 3 products.
c) Explain why 3,4-dibromo-3-methyl-1-butene (21 %) predominates over 3,4-dibromo-2-
methyl-1-butene (3 %).
2.3 Assuming that the nitrogen in enamine is sp2 hybridized, explain why the double bond of
an enamine is more nucleophilic than a typical alkene double bond.
3.2 The reaction of methylpropene with HBr, under radical conditions, gives two
intermediates. Propose a mechanism for the formation of the two products.
3.4 Draw the structure of an antioxidant, Vitamin E free radical and use resonance structures
to account for its stability
Elucidate enzymes under the following sub headings:
Properties and classification
Enzyme kinetics
Enzyme inhibition and regulation
Role of enzymes in clinical diagnostics
1.3 Draw structures of aniline and cyclohexylamine and use appropriate factors to compare
their basicity.
1.4 Explain why AlCl3 is a stronger Lewis acid than Al(CH3)3
