Hello,
I am writing an examination tomorrow in chemical calculations. I am not really good in it, I have been battling with these questions but later decided to post it for fellow nairalanders to help me out with them.
Thank you

Ka for the acid ionization of Fe3+ to Fe(OH)2+ and H+ is 6.5*10^(-3)?

What is the pH which could be used so that 95% of the total Fe(III) iron in a dilute aqueous solution is in the free Fe3+ form? Do not use any assumptions!
Formulate the corresponding reaction equation for the formation of protons upon dissolving a Fe3+ salt in water!

The insecticide chloropicrin CCl3NO2 is produced according to the reaction equation?

CH3NO2 + Cl2------------> CCl3NO2 + HCl
500g of the insecticide have to be made. Calculate the required volume of chlorine gas under STP that have to be applied!

Lithium(I)oxide is an efficient chemical absorber and is used in short spaceflights to remove exhaled CO2.?
Upon absorption lithium(I)carbonate is formed!

a) Formulate the corresponding reaction equation!
b) How many litres of CO2 are absorbed under STP per each kg of lithium(I)oxide?

250ml sulfuric acid are titrated with 0.1M NaOH. A few drops methyl orange are added as indicator.?

When 23.60ml of NaOH is added, a colour change from red to yellow occurs. Calculate the amount of sulfuric acid in grams, which are in 250ml sulfuric acid.

oboy dis one go hard for merlin o, All diz na one question I hope NL gurus wud be able to help, Lots of luck bro,

PTFE- polymers (CF2)x are made according to the following reaction: (the x here is a subscript)?
(CH2)x + 4xCoF3 --------> (CF2)x +2xHF +4xCoF2
(the x in CH2 and CF2 are subscripts)

where x is a large integer.
The required CoF3 is obtained by flourination of CoF2:
2CoF2 +F2------->2CoF3

a) If the HF formed in the first reaction cannot be reused, how many kg of flourine are consumed per each kg of flourocarbon polymer produced?

b) If the HF can be recovered and electrolyzed according to
2HF---------->H2+F2
and if this flourine is used for regenerating CoF3, what is the net consumption of flourine (in kg) per kg of PTFE?

In a blast furnace, 1 ton of Iron(III)oxide is reduced with CO yielding iron, according to this equation:?
Fe2O3+3CO------->2Fe + 3CO2
The turnover of Fe(III)oxide has a value of 88.4%

a) calculate the amount of Fe in kg, that is produced in this reaction.
b) calculate the amount of CO2 in kg.
c) calculate the number of molecules of CO, that were involved in the reaction.

Thank you all for your answers!!!!!!!!!!!!!!!

In 250ml of an aqueous solution 265 mg sodium carbonate is dissolved.

Calculate the amount of silver nitrate in grams, that can be added to this solution, without precipitation of silver carbonate occuring!

pKl(Ag2CO3) = 11.28

Neglect the protolysis of the carbonate anions!

The solubility product of AgCl Kl(AgCl) is 1.20*10^(-10)mol^2*l^(-2).?
Calculate the solubility of AgCl,
a) in pure water!
b) in an aqueous solution of chloride ions with the concentration of c(Cl-)=10^(-3)mol/l

Please can the moderator put this on the homepage?