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Consider the structure of nicotine below and answer the questions that follow. [2] a) What is the hybridization of each N atom in Nicotine?
what is the molality of 40.0g KBr dissolved in 800.0g water
What structural characteristics are common to all the amino acids that are found in
mammalian proteins and draw the structure of the tripeptide His-Pro-Tyr in the ionic form
that predominates at pH 7. Draw all atoms (including hydrogens) as well as any charges as
necessary. (10)
1
The ammonium ion (pKa = 9.25) has a lower pKa than the methyl ammonium ion (pKa = 10.66).
Explain which of the two species is the stronger base is
The partial pressure of chlorine in a mixture of a gases where the total pressure is 1.00 atm is 350 mmHg.What is the mole fraction of chlorine?
2.83 g of a sample of haematite iron ore [iron (III) oxide, Fe2O3] were dissolved in concentrated hydrochloric acid and the solution diluted to 250 cm3. 25.0 cm3 of this solution was reduced with tin(II) chloride (which is oxidised to Sn4+ in the process) to form a solution of iron(II) ions. This solution of iron(II) ions required 26.4 cm3 of a 0.0200 mol/dm3 potassium dichromate(VI) solution for complete oxidation back to iron(III) ions.
(a) given the half–cell reactions
(i) Sn4+(aq) + 2e– ==> Sn2+(aq)
and (ii) Cr2O72–(aq) + 14H+(aq) + 6e– ==> 2Cr3+(aq) + 7H2O(l)
deduce the fully balanced redox equations for the reactions
(i) the reduction of iron(III) ions by tin(II) ions
(ii) the oxidation of iron(II) ions by the dichromate(VI) ion
(b) Calculate the percentage of iron(III) oxide in the ore.
What is the [OH] in a solution that has a pH = 4.02?
Salt is often used to melt ice and snow on roads in the winter and the temperature right now is -4.500°C. How much NaCl (complete dissociation) would be necessary to melt 1000kg of ice by bringing down the freezing temperature to -4.500°C?
A solution 2 g nonelectrolyte solute in 0.200 kg water boils at 102C. What is the molar mass of the solute added?
Calculate the amount of energy (in KJ) needed to heat 346 gram of liquid water from 0 °C to 182 °C. Assume that the specific heat of water is 4.184 J/g °C over the entire liquid range and the specific heat of stream is 1.99 J/g °C
