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- A gas system with constant pressure has change in internal energy of 240 J. Heat was lost to the surroundings and 150 J work was done to the surroundings as well. How many calories of heat was lost?
Question 2
The silver concentration in a sample of photographic waste was determined by AAS. Table 3 shows the results obtained. Is the calibration data linear? Plot the calibration curve. [25 Marks]
Table 3: Determination of silver concentration by AAS
Added Ag: µg added per ml of original solution 0 5 10 15 20 25 30
Absorbance 0.32 0.41 0.52 0.60 0.70 0.77 0.89
Question 1
Table 2 gives the recovery of bromide from spiked samples of vegetable matter, measured by Gas-liquid chromatographic method. The same amount of bromide was added to each specimen.
Table 2: Recovery of bromide from spiked samples of vegetable matter
Tomato 777 790 759 790 770 758 764
Cucumber 782 773 778 765 789 797 782
a) Test whether the recoveries from the two vegetables have variances which differ significantly. [10 Marks]
b) Test whether the mean recovery rates differ significantly.
Calculate the Kc of the reaction below if the equilibrium concentrations of Ag and IO3 are both 1.78×10-⁴M
Write the Kc expression for the reversible reaction of PCI5 done at equilibrium conditions.
1.Color and phase
Solid, silvery white
Liquid silvery
2.Melting point
660°C
3.Electrical Conductivity
Conductor
Conductor
So, give the balanced formula for rusting, 4Fe+3O2+6H2O= 4Fe(OH)3, what would be the charges of the 4 iron atoms at the beginning, meaning how many valance electrons would they have? I understand this is a really dumb question, but i can just not find the answer. Can anyone kindly help my stupid self, please?
Calculate the number of moles of hydrogen atoms in one mole of (NH4)2SO4.
[1] 1
[2] 2
[3] 4
[4] 8
[5] 15
Identify the type of reagent that is required to convert N2H4 to N2?
[1] acid
[2] base
[3] reducing agent
[4] oxidizing agent
[5] precipitating agent
By applying the solubility guidelines, state which of the following compounds will precipitate in water?
[1] Cobalt (II) hydroxide.
[2] Sodium nitrate.
[3] Ammonium phosphate.
[4] Potassium Chloride.
[5] None of the above.
